Formulations of guanylate cyclase c agonists and methods of use

ABSTRACT

The invention provides novel formulations of guanylate cyclase-C(“GCC”) agonist peptides and methods for their use in the treatment of gastrointestinal diseases and disorders, including gastrointestinal cancer. The GCC agonist formulations of the invention can be administered either alone or in combination with one or more additional therapeutic agents, preferably an inhibitor of cGMP-dependent phosphodiesterase or a laxative.

RELATED APPLICATIONS

This application is a continuation of U.S. Utility application Ser. No. 12/630,565, filed on Dec. 3, 2009 and claims the benefit of priority to U.S. Provisional Application No. 61/119,521 filed on Dec. 3, 2008, the contents of which are incorporated by reference in their entireties.

STATEMENT REGARDING SEQUENCE LISTING

The Sequence Listing associated with this application is provided in text format in lieu of a paper copy, and is hereby incorporated by reference into the specification. The name of the text file containing the Sequence Listing is SYPA_(—)007_C01US_ST25.txt. The text file is about 116 KB, was created on Jun. 11, 2014, and is being submitted electronically via EFS-Web.

FIELD OF THE INVENTION

The present invention relates to novel formulations of guanylate cyclase C agonists which are optimized for delivery to specific regions of the gastrointestinal tract and are useful for the treatment and prevention of gastrointestinal diseases and disorders.

BACKGROUND OF THE INVENTION

Guanylate cyclase C is a transmembrane form of guanylate cyclase that is expressed on various cells, including gastrointestinal epithelial cells (reviewed in Vaandrager 2002 Mol. Cell. Biochem. 230:73-83). It was originally discovered as the intestinal receptor for the heat-stable toxin (ST) peptides secreted by enteric bacteria and which cause diarrhea. The ST peptides share a similar primary amino acid structure with two peptides isolated from intestinal mucosa and urine, guanylin and uroguanylin (Currie, et al., Proc. Nat'l Acad. Sci. USA 89:947-951 (1992); Hamra, et al., Proc. Nat'l Acad. Sci. USA 90:10464-10468 (1993); Forte, L., Reg. Pept. 81:25-39 (1999); Schulz, et al., Cell 63:941-948 (1990); Guba, et al., Gastroenterology 111:1558-1568 (1996); Joo, et al., Am. J. Physiol. 274:G633-G644 (1998)).

In the intestines, guanylin and uroguanylin act as regulators of fluid and electrolyte balance. In response to high oral salt intake, these peptides are released into the intestinal lumen where they bind to guanylate cyclase C localized on the luminal membrane of enterocytes (simple columnar epithelial cells of the small intestines and colon). The binding of the guanylin peptides to guanylate cyclase C induces electrolyte and water excretion into the intestinal lumen via a complex intracellular signaling cascade that is initiated by an increase in cyclic guanosine monophosphate (cGMP).

The cGMP-mediated signaling that is initiated by the guanylin peptides is critical for the normal functioning of the gut. Any abnormality in this process could lead to gastrointestinal disorders such as irritable bowel syndrome (IBS) and inflammatory bowel diseases. Inflammatory bowel disease is a general name given to a group of disorders that cause the intestines to become inflamed, characterized by red and swollen tissue. Examples include ulcerative colitis and Crohn's disease. Crohn's disease is a serious inflammatory disease that predominantly affects the ileum and colon, but can also occur in other sections of the gastrointestinal tract. Ulcerative colitis is exclusively an inflammatory disease of the colon, the large intestine. Unlike Crohn's disease, in which all layers of the intestine are involved, and in which there can be normal healthy bowel in between patches of diseased bowel, ulcerative colitis affects only the innermost lining (mucosa) of the colon in a continuous manner. Depending on which portion of the gastrointestinal tract is involved, Crohn's disease may be referred to as ileitis, regional enteritis, colitis, etc. Crohn's disease and ulcerative colitis differ from spastic colon or irritable bowel syndrome, which are motility disorders of the gastrointestinal tract. Gastrointestinal inflammation can be a chronic condition. It is estimated that as many as 1,000,000 Americans are afflicted with inflammatory bowel disease, with male and female patients appearing to be equally affected. Most cases are diagnosed before age 30, but the disease can occur in the sixth, seventh, and later decades of life.

IBS and chronic idiopathic constipation are pathological conditions that can cause a great deal of intestinal discomfort and distress but unlike the inflammatory bowel diseases, IBS does not cause the serious inflammation or changes in bowel tissue and it is not thought to increase the risk of colorectal cancer. In the past, inflammatory bowel disease, celiac disease and IBS were regarded as completely separate disorders. Now, with the description of inflammation, albeit low-grade, in IBS, and of symptom overlap between IBS and celiac disease, this contention has come under question. Acute bacterial gastroenteritis is the strongest risk factor identified to date for the subsequent development of postinfective irritable bowel syndrome. Clinical risk factors include prolonged acute illness and the absence of vomiting. A genetically determined susceptibility to inflammatory stimuli may also be a risk factor for irritable bowel syndrome. The underlying pathophysiology indicates increased intestinal permeability and low-grade inflammation, as well as altered motility and visceral sensitivity. Serotonin (5-hydroxytryptamine[5-HT]) is a key modulator of gut function and is known to play a major role in pathophysiology of IBS. The activity of 5-HT is regulated by cGMP.

While the precise causes of IBS and inflammatory bowel diseases (IBD) are not known, a disruption in the process of continual renewal of the gastrointestinal mucosa may contribute to disease pathology in IBD and aggravate IBS. The renewal process of the gastrointestinal lining is an efficient and dynamic process involving the continual proliferation and replenishment of unwanted damaged cells. Proliferation rates of cells lining the gastrointestinal mucosa are very high, second only to the hematopoietic system. Gastrointestinal homeostasis depends on both the proliferation and programmed cellular death (apoptosis) of epithelial cells lining the gut mucosa. Cells are continually lost from the villus into the lumen of the gut and are replenished at a substantially equal rate by the proliferation of cells in the crypts, followed by their upward movement to the villus. The rates of cell proliferation and apoptosis in the gut epithelium can be increased or decreased in a variety of circumstances, e.g., in response to physiological stimuli such as aging, inflammatory signals, hormones, peptides, growth factors, chemicals and dietary habits. In addition, an enhanced proliferation rate is frequently associated with a reduction in turnover time and an expansion of the proliferative zone. The proliferation index is much higher in pathological states such as ulcerative colitis and other gastrointestinal disorders. Intestinal hyperplasia is a major promoter of gastrointestinal inflammation. Apoptosis and cell proliferation together regulate cell number and determine the proliferation index. Reduced rates of apoptosis are often associated with abnormal growth, inflammation, and neoplastic transformation. Thus, both increased proliferation and/or reduced cell death may increase the proliferation index of intestinal tissue, which may in turn lead to gastrointestinal inflammatory diseases.

In addition to a role for uroguanylin and guanylin as modulators of intestinal fluid and ion secretion, these peptides may also be involved in the continual renewal of gastrointestinal mucosa by maintaining the balance between proliferation and apoptosis. For example, uroguanylin and guanylin peptides appear to promote apoptosis by controlling cellular ion flux. Given the prevalence of inflammatory conditions in Western societies a need exists to improve the treatment options for inflammatory conditions, particularly of the gastrointestinal tract.

SUMMARY OF THE INVENTION

The present invention provides novel formulations of guanylate cyclase C agonists (“GCC agonists”) which are optimized for the targeted delivery of the agonist to a specific portion of the gastrointestinal tract, for example, to the small intestines, preferably to the duodenum or jejunum, or to the distal small intestines or the large intestines, preferably the ileum, terminal ileum, or ascending colon. The formulations optimized for delivery of a GCC agonist to the duodenum or jejunum are particularly useful for the treatment or prevention of a disease or disorder selected from the group consisting of irritable bowel syndrome (preferably constipation predominant) non-ulcer dyspepsia, chronic intestinal pseudo-obstruction, functional dyspepsia, colonic pseudo-obstruction, duodenogastric reflux, gastro esophageal reflux disease, chronic idiopathic constipation, gastroparesis, heartburn, gastric cancer, and H. pylori infection. The formulations optimized for delivery of a GCC agonist to the ileum, terminal ileum, or ascending colon are particularly useful for the treatment or prevention of a disease or disorder selected from the group consisting of ileitis (e.g., post-operative ileitis), Crohn's disease, ulcerative colitis, terminal ileitis, and colon cancer.

The targeted GCC agonist formulations of the invention offer several advantages over other formulations, especially conventional oral formulations. Because GCC agonists can potentially act throughout the gastrointestinal tract, conventional oral formulations intended to treat IBD, for instance, may exhibit side effects due to the activity of the GCC agonist in non-target tissues. One such side effect is diarrhea, which could interfere with treatment by a GCC agonist of GI diseases such as ulcerative colitis and Crohn's disease. Conventional oral formulations also suffer from degradation or aggregation of the GCC agonist in the stomach due to the low pH environment (Marx et al., 1998 Peptide Res. 52:229-240; Chino et al., 1998 FEBS Let. 421:27-31). In contrast, the GCC agonist formulations of the invention are optimized for the release of the GCC agonist to the target tissue, either the small intestines or the large intestines, depending on the disease or disorder to be treated. Such formulations minimize exposure of the GCC agonist peptide to stomach acidity, thereby reducing or eliminating the degradation and aggregation that occur under low pH conditions. Other advantages of the GCC agonist formulations of the invention include fewer side effects caused by unwanted GCC activity in non-target tissues. In addition, the GCC agonists formulated according to the invention may be given at a lower effective dose than a conventional oral dosage form. In other embodiments, the GCC agonist formulation of the invention delivers a higher effective dose to the target tissue than a conventional oral dosage form with reduced side effects compared to a conventional oral dosage form.

In certain embodiments, the GCC agonists are analogs of uroguanylin and bacterial ST peptides. In preferred embodiments, the analogs have superior properties compared to the naturally occurring or “wild-type” peptides. Examples of such superior properties include a high resistance to degradation at the N-terminus and C-terminus from carboxypeptidases, aminopeptidases, and/or by other proteolytic enzymes present in the stimulated human intestinal juices and human gastric juices. Examples of GCC agonists that can be used in the formulations and methods of the invention are described in more detail below.

In one embodiment, the GCC agonist formulation comprises (1) a core, which contains at least one GCC agonist peptide, and (2) one or more targeting materials selected from the group consisting of a pH-dependent polymer, a swellable polymer, and a degradable composition, wherein the GCC agonist peptide is selected from the group consisting of SEQ ID NOs: 1-249. In a preferred embodiment, the GCC agonist peptide is selected from the group consisting of SEQ ID NOs: 1, 8, 9, 55 or 56. In one embodiment, the GCC agonist peptide is selected from the group consisting of SEQ ID NOs: 1 and 9. In certain embodiments, the one or more targeting materials form one or more layers around the core. In certain embodiments, at least one targeting material forms a matrix with the GCC agonist peptide of the core. Preferably, the formulation is for oral administration.

In one embodiment, the GCC agonist formulation is optimized for delivery of a GCC agonist to the duodenum or jejunum and comprises one or more pH dependent polymers which degrade in a pH range of 4.5 to 5.5, wherein the pH dependent polymers form one or more layers around the core.

In one embodiment, the GCC agonist formulation is optimized for delivery of a GCC agonist to the ileum, terminal ileum, or ascending colon and comprises one or more pH dependent polymers which degrade in a pH range of 5.5 to 6.5 or in a pH range of 6.5 to 7.5, wherein the pH dependent polymers form one or more layers around the core. In one embodiment, the one or more pH dependent polymers degrade at pH above 5.5. In another embodiment, the one or more pH dependent polymers degrade at pH above 7. In one embodiment, the formulation further comprises a swellable polymer interposed between two layers of pH dependent polymers. Preferably, the swellable polymer is selected from the group consisting of an acrylic copolymer, polyvinylacetate, and cellulose derivatives. In one embodiment, the swellable polymer is an acrylic copolymer selected from the group consisting of EUDRAGIT RL, EUDRAGIT RS, and EUDRAGIT NE. In one embodiment, the formulation further comprises a pore forming agent. In specific embodiments, the pore forming agent is selected from the group consisting of saccharose, sodium chloride, potassium chloride, polyvinylpyrrolidone, polyethyleneglycol, water soluble organic acids, sugars and sugar alcohol.

The pH dependent polymers for use in the formulations of the invention are preferably selected from the group consisting of a methacrylic acid copolymer, a polyvinyl acetate phthalate, a hydroxypropylmethylcellulose phthalate, a cellulose acetate trimelliate, a cellulose acetate phthalate, or a hydroxypropyl methyl cellulose acetate succinate. In one embodiment, at least one of the pH dependent polymers is a methacrylic acid copolymer. In a preferred embodiment, the methacrylic acid copolymer is selected from among the EUDRAGIT polymers. In a particular embodiment, the EUDRAGIT polymer is selected from among the group consisting of EUDRAGIT L100, EUDRAGIT L-30D, EUDRAGIT S100, EUDRAGIT FS 30D, and EUDRAGIT L100-55, and combinations thereof.

In one embodiment, the GCC agonist formulation comprises a degradable composition. In certain embodiments, the degradable composition is selected from the group consisting of amylase, chitosan, chondroitin sulfate, cyclodextrin, dextran, guar gum, pectin, and xylan. Preferably, the degradable composition is coated with a material selected from the group consisting of cellulose acetate phthalate, hydroxy propyl methyl cellulose acetate succinate, EUDRAGIT L100 and EUDRAGIT L30D-55.

In another embodiment, the degradable composition is a carrier molecule linked to the GCC agonist by a covalent bond, wherein the covalent bond is stable in the stomach and small intestines but labile in the lower gastrointestinal tract, especially the colon. Preferably, the covalent bond is an azo bond or a glycosidic bond. In a specific embodiment, the carrier molecule is selected from the group consisting of a glucuronide, a cyclodextrin, a dextran ester, or a polar amino acid.

The invention also provides methods for treating or preventing a gastrointestinal disease or disorder in a subject in need thereof, comprising administering to the subject a GCC agonist formulation comprising (1) a core, which contains at least one GCC agonist peptide, and (2) one or more targeting materials selected from the group consisting of a pH-dependent polymer, a swellable polymer, and a degradable composition, wherein the GCC agonist peptide is selected from the group consisting of SEQ ID NOs: 1-249. In certain embodiments, the one or more targeting materials form one or more layers around the core. In certain embodiments, at least one targeting material forms a matrix with the GCC agonist peptide of the core. Preferably, the formulation is for oral administration.

In one embodiment, the formulation comprises one or more pH dependent polymers which degrade in a pH range of 4.5 to 5.5 and the gastrointestinal disease or disorder is selected from the group consisting of irritable bowel syndrome (preferably constipation predominant), non-ulcer dyspepsia, chronic intestinal pseudo-obstruction, functional dyspepsia, colonic pseudo-obstruction, duodenogastric reflux, gastro esophageal reflux disease, chronic idiopathic constipation, gastroparesis, heartburn, gastric cancer, and H. pylori infection. In one embodiment, the gastrointestinal disease or disorder is selected from the group consisting of chronic idiopathic constipation and irritable bowel syndrome.

In one embodiment, the formulation comprises one or more pH dependent polymers which degrade in a pH range of 6.5 to 7.5 and the gastrointestinal disease or disorder is selected from the group consisting of ileitis (post-operative ileitis), Crohn's disease, ulcerative colitis, terminal ileitis, and colon cancer. In one embodiment, the gastrointestinal disease or disorder is selected from the group consisting of ulcerative colitis and Crohn's disease.

In a preferred embodiment, the method for treating or preventing a gastrointestinal disease or disorder in a subject in need thereof comprises administering to the subject a GCC agonist formulation comprising a GCC agonist peptide selected from the group consisting of SEQ ID NOs: 1, 8, 9, 55 or 56. In one embodiment, the GCC agonist peptide is selected from the group consisting of SEQ ID NOs: 1 and 9.

In one embodiment, the method further comprises administering to the subject an effective amount of an inhibitor of a cGMP-specific phosphodiesterase. In a specific embodiment, the cGMP-dependent phosphodiesterase inhibitor is selected from the group consisting of suldinac sulfone, zaprinast, and motapizone, vardenifil, and suldenifil.

In one embodiment, the method further comprises administering to the subject an effective amount of at least one laxative. In one embodiment, the at least one laxative is selected from the group consisting of SENNA, MIRALAX, PEG, or calcium polycarbophil.

In one embodiment, the method further comprises administering to the subject an effective amount of at least one anti-inflammatory agent.

In a preferred embodiment, the subject is a human.

Other features and advantages of the invention will be apparent from and are encompassed by the following detailed description and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A: Biological activity of SP-304 incubated for varying lengths of time in simulated gastric fluid (SGF). The biological activity of SP-304 was determined by measuring its ability to stimulate cGMP synthesis in T84 cells. Samples incubated for 0, 15, 30, 60, 90 and 120 minutes, respectively, were collected and analyzed for biological activity—with activity of the 0 min sample defined as 100% biological activity. The activities of the other samples are shown as percentage activity relative to the 0 min activity sample. Data points shown are the average of triplicate measurements±SD.

FIG. 1B: Schematic representation of HPLC chromatographic analyses of SP-304 samples after incubation with SGF for 0 and 120 min, respectively. The arrows show the elution position of SP-304.

FIG. 2A: Biological activity of SP-304 incubated for varying lengths of time in simulated intestinal fluid (SIF). SP-304 samples were incubated for 0, 30, 60, 90, 150, and 300 min, respectively, and then tested for their ability to stimulate cGMP synthesis in T84 cells. The cGMP stimulation activity in the sample at 0 min of incubation time in SIF was taken as 100% biological activity. The activities of the other SP-304 incubation samples were calculated as the percentage of activity relative to that of the 0 min sample. Data points shown are the average of triplicate measurements±SD.

FIG. 2B: HPLC chromatographic spectra of SP-304 samples after incubation with: (A) heat-inactivated SIF for 300 minutes, or (B) SIF for 120 minutes. The arrows show the elution position of SP-304. The treatment with SIF completely eliminated SP-304 after a 2-hr incubation and a peptide signal appeared, eluting at 9.4 min, as indicated by *.

FIG. 3: Schematic representation of possible degradation products of SP-304.

FIG. 4: Biological activity of truncated peptides of 16-mer SP-304, as measured by stimulation of cGMP synthesis in T84 cells. SP-338 15-mer peptide is identical to SP-304 except that it lacks Leu at the C-terminus. SP-327, SP-329 and SP-331 lack Leu at their C-termini relative to their corresponding parents, SP-326, SP-328 and SP-330, respectively. Data points shown are the average of duplicate measurements.

FIG. 5: Stimulation of cGMP synthesis in T84 cells by SP-304 and similar analogs. T84 cells were exposed to test peptides for 30 min and cell lysates were then used to determine intracellular cGMP levels. Data points shown are the average of triplicate measurements±SD.

FIG. 6: Stimulation of cGMP synthesis in T84 cells by SP-339 (linaclotide) and other linaclotide analogs. T84 cells were exposed to test peptides for 30 min and cell lysates were then used to determine intracellular cGMP levels. Data points shown are the average of triplicate measurements±SD.

FIG. 7A: Biological activity of SP-333 incubated for varying lengths of time in simulated intestinal fluid (SIF). SP-333 samples incubated for 0, 5, 10, 30, 60, and 120 min, respectively, were tested for their ability to stimulate cGMP synthesis in T84 cells. The control sample marked as C120 was produced by incubating SP-333 with heat inactivated SIF for 120 min. Samples from the incubations were removed and heated at 95° C. for 5 min to inactivate digestive enzymes and then used to stimulate cyclic GMP synthesis in T84 cells. The cGMP stimulation activity in the sample at 0 min of incubation time in SIF was taken as 100% biological activity. The activities of the other SP-304 incubation samples were calculated as the percentage of activity relative to that of the 0 min sample. Data points shown are the average of triplicate measurements±SD.

FIG. 7B: Biological activity of SP-332 incubated for varying lengths of time in simulated intestinal fluid (SIF). SP-333 samples incubated for 0, 5, 10, 30, 60, and 120 min, respectively, were tested for their ability to stimulate cGMP synthesis in T84 cells. The control sample marked as C120 was produced by incubating SP-332 with heat inactivated SIF for 120 min. Samples from the incubations were removed and heated at 95° C. for 5 min to inactivate digestive enzymes and then used to stimulate cyclic GMP synthesis in T84 cells. The cGMP stimulation activity in the sample at 0 min of incubation time in SIF was taken as 100% biological activity. The activities of the other SP-304 incubation samples were calculated as the percentage of activity relative to that of the 0 min sample. Data points shown are the average of triplicate measurements±SD.

FIG. 7C: Biological activity of SP-304 incubated for varying lengths of time in simulated intestinal fluid (SIF). SP-304 samples incubated for 0, 10, and 60 min, respectively, were tested for their ability to stimulate cGMP synthesis in T84 cells. The control samples marked as C0 and C60 were produced by incubating SP-304 with heat inactivated SIF for 0 and 60 min, respectively. Samples from the incubations were removed and heated at 95° C. for 5 min to inactivate digestive enzymes and then used to stimulate cyclic GMP synthesis in T84 cells. The cGMP stimulation activity in the sample at 0 min of incubation time in SIF was taken as 100% biological activity. The activities of the other SP-304 incubation samples were calculated as the percentage of activity relative to that of the 0 min sample. Data points shown are the average of triplicate measurements±SD.

FIGS. 7D-1-7D-2: HPLC chromatograms of SP-304 incubated for 0 min in SIF (FIG. 7D-1) and 60 min in SIF (FIG. 7D-2), respectively. The arrows indicate the elution positions of the parent SP-304 peptides. The data clearly show that the SP-304 peak eluting at 14.3 min completely vanished and two new peaks emerged at 7.4 and 10.3 minutes. These new peptide peaks represent degradation products of SP-304.

FIGS. 7E-1-7-E2: HPLC chromatograms of SP-332 incubated for 0 min in SIF (FIG. 7E-1) and 120 min in SIF (FIG. 7E-2), respectively. The arrows indicate the elution positions of the parent SP-332 peptides. The data show that the peptide SP-332 eluting at 14.8 minutes remained intact following incubation with SIF for 120 min, suggesting that SP-332 is resistant to proteolysis by proteases present in SIF.

FIGS. 7F-1-7F-2: HPLC chromatograms of SP-333 incubated for 0 min in SIF (FIG. 7F-1) and 120 min in SIF (FIG. 7F-2), respectively. The arrows indicate the elution positions of the parent SP-333 peptides. The data show that peptide SP-333, eluting at 14.8 minutes remained intact following incubation with SIF, suggesting that SP-333 is resistant to proteolysis by proteases present in SIF during the 120 minute incubation period.

FIGS. 7G-1-7G-5: Incubation of SP-333 with SIF for 2, 6, 12 and 24 hrs. Effect of SIF digestion on the activity of SP-333 in T84 stimulation assay was determined (FIG. 7G-1) and samples were also analyzed by HPLC (FIGS. 7G2-5). The elution positions of the parent peptide and its metabolites are indicated by arrows.

FIG. 8: Stimulation of cGMP synthesis in T84 cells by the pegylated analogs of SP-333. T84 cells were exposed to the indicated peptides for 30 min and cell lysates were used to determine intracellular cGMP levels. Data points shown are the average of triplicate measurements±SD.

FIG. 9: Stimulation of cGMP synthesis in T84 cells by SP-304 (0.1 μM) either alone or in combination with the phosphodiesterase (PDE) inhibitors Sulindac Sulfone (100 μM) or Zaprinast (100 μM). T84 cells were exposed to various treatments, as indicated, for 30 min and the cell lysates were used to determine the intracellular cGMP levels. Data points shown are the average of duplicate measurements.

FIG. 10: Stimulation of cGMP synthesis in T84 cells by SP-304 (0.1 or 1.0 μM) either alone or in combination with incremental concentrations of phosphodiesterase (PDE) inhibitors, as indicated. T84 cells were exposed to various treatments, as indicated, for 30 min and the cell lysates were used to determine the intracellular cGMP levels. Data points shown are the average of duplicate measurements.

FIG. 11: Stimulation of cGMP synthesis in T84 by SP-333 (0.1 or 1.0 μM) either alone or in combination with incremental concentrations of Zaprinast, as indicated. T84 cells were exposed to various treatments, as indicated, for 30 min and the cell lysates were used to determine the intracellular cGMP levels. Data points shown are the average of duplicate measurements.

FIG. 12: Stimulation of cGMP synthesis in T84 by SP-333 (0.1 μM) either alone or in combination with incremental concentrations of Sulindac Sulfone, as indicated. T84 cells were exposed to various treatments, as indicated, for 30 min and the cell lysates were used to determine the intracellular cGMP levels. Data points shown are the average of duplicate measurements.

FIG. 13: SP-304 treatment improved stool consistency and clears TNBS-induced intestinal blockage in a TNBS-induced murine model of colitis.

FIG. 14: SP-304 treatment stimulated increased water flow in the lumen of the GI tract of cynomolgus monkeys.

FIG. 15A-B: The effect of SP-304 administration on stool consistency in human volunteers as judged by the Bristol Score of the first bowel movement. Results from a phase 1, single-site, randomized, double-blind, placebo-controlled, single-, ascending-, oral-dose, sequential dose escalation study of SP-304 in fasted, healthy male and female subjects. A total of 9 cohorts utilizing 8 subjects per cohort (6 SP-304; 2 placebos) were utilized, totaling 71 volunteers administered drug. Each cohort was administered a single, oral dose or matching placebo administered in 10-fold diluted phosphate buffered saline (PBS) (240 mL). The nine cohort doses included 0.1, 0.3, 0.9, 2.7, 5.4, 8.1, 16.2, 24.3 and 48.6 mg SP-304.

FIG. 16: The effect of SP-304 administration on average time to first stool through 24 hours post-dose in human volunteers. Results from a phase 1, single-site, randomized, double-blind, placebo-controlled, single-, ascending-, oral-dose, sequential dose escalation study of SP-304 in fasted, healthy male and female subjects. A total of 9 cohorts utilizing 8 subjects per cohort (6 SP-304; 2 placebos) were utilized, totaling 71 volunteers administered drug. Each cohort was administered a single, oral dose or matching placebo administered in 10-fold diluted phosphate buffered saline (PBS) (240 mL). The nine cohort doses included 0.1, 0.3, 0.9, 2.7, 5.4, 8.1, 16.2, 24.3 and 48.6 mg SP-304.

FIGS. 17A-B: SP-304 exhibited superior activity compared to Sulfasalazine to ameliorate inflammation in DSS-induced colitis in BDF-1 mice.

FIG. 18: SP-304 showed superior activity compared to Sulfasalazine to ameliorate inflammation in TNBS-induced colitis in BDF-1 mice.

FIG. 19: Determination of SP-304 dose that produced diarrhea in monkeys. Two groups of monkeys, male and female, were treated with a single dose of SP-304 per day continuously for 28 days (for each group, 0 and 75 mg/kg, n=5; 1, 10 mg/kg, n=4). Stool consistency and bowel frequency were noted every day. Results are presented as cumulative score for 28 days. The scoring used for stool consistency was as follows: 0: No stool, 1: Normal stool, 2: Loose/mushy stool and 3: Diarrhea/watery stool.

FIG. 20: SP-304 formulated for pH dependent release. Gelatin capsules were filled with calculated quantity of SP-304 (10 mg/kg body weight). Capsules were coated with either EUDRAGIT polymer L 30 D-55 (for release at pH greater than 5.5; Lot No. B081214690) or EUDRAGIT polymer FSD (for release at pH greater than 7; Lot No. G090365030). One capsules from each formulation were placed in a plastic tube containing 50 ml of buffer saline solution adjusted to either pH 5.7 or pH 7.2. Uncoated gelatin capsules containing the same quantity of SP-304 were used as controls. All controls were incubated in a buffered saline solution adjusted to pH 1.0. The plastic tubes were incubated on a rotatory shaker in a 37° C. incubator. Samples (0.5 ml) were withdrawn from the tube at the indicated time intervals and immediately subjected to HPLC analysis to determine the release of SP-304 in the solution. The capsule coated with EUDRAGIT polymer L 30 D-55 (for release at pH greater than 5.5) was incubated at pH 2.5 for 60 min to mimic exposure to stomach acidity. The same capsule was removed and placed in buffer saline solution (pH 5.7) and samples were withdrawn at different times for HPLC analysis. Similarly, the capsule coated with EUDRAGIT polymer FSD (for release at pH greater than 7) was sequentially incubated at pH 2.5 (60 min), pH 5.5 (60 min) and then at pH 7.0 for the indicated time interval for sampling.

FIGS. 21A-C: Bioactivity of SP-304 formulated for pH dependent release. Gelatin capsules were filled with calculated quantity of SP-304 (10 mg/kg body weight). Capsules were coated with EUDRAGIT polymer following the standard procedure for release at either pH greater than 5.5 or greater than 7. One capsule from each formulation was placed in a plastic tube containing 50 ml of buffer saline solution adjusted to either pH 5.7 or pH 7.2. Uncoated gelatin capsules containing the same quantity of SP-304 were used as controls. The plastic tubes were incubated on a rotatory shaker in a 37° C. incubator. Samples (0.5 ml) were withdrawn from the tube at the indicated time intervals and immediately used for the bioassay using T84 cells to determine the release of SP-304 in the solution. The capsule coated with EUDRAGIT polymer L 30 D-55 (for release at pH greater than 5.5) was incubated at pH 2.5 for 60 min to mimic exposure to stomach acidity. The same capsule was removed and placed in buffer saline solution (pH 5.7) and samples were withdrawn at different times for bioassay. Similarly, the capsule coated with EUDRAGIT polymer FSD (for release at pH greater than 7) was sequentially incubated at pH 2.5 (60 min), pH 5.5 (60 min) and then at pH 7.0 for the indicated time interval and samples were withdrawn for bioassay.

FIG. 22: Formulation to deliver SP-304 at pH greater than 7.0 reduced incidence of diarrhea in monkeys. Gelatin capsules were filled with SP-304 to produce a dose of 10 mg/kg body weight. Capsules were coated with EUDRAGIT polymer FSD. Uncoated capsules were used in the control group of monkeys. Effect of treatment was assessed on stool consistency. Results are expressed as cumulative scores of the number of diarrhea incidences in the seven days of treatment period.

FIGS. 23A-B: Formulation to deliver SP-333 at pH greater than 7.0 reduced incidence of diarrhea in monkeys. Gelatin capsules were filled with SP-333 to produce a dose of 10 mg/kg body weight. Capsules were coated with EUDRAGIT polymer FSD. Uncoated capsules were used in the control group of monkeys. Effect of treatment was assessed on stool consistency. Results are expressed as cumulative scores of the number of diarrhea incidences in the seven days of treatment period.

DETAILED DESCRIPTION

The present invention provides novel formulations of GCC agonists which target the release of the GCC agonist to a specific region of the gastrointestinal tract, namely either to the proximal small intestines, preferably the duodenum or jejunum, or to the distal small intestines or large intestines, preferably the ileum, terminal ileum, or ascending colon. The targeted release GCC agonist formulations of the invention are useful for the treatment or prevention of gastrointestinal diseases and disorders. In particular, the formulations which target to the duodenum or jejunum are useful for the treatment or prevention of one or more of the following: irritable bowel syndrome (preferably constipation predominant), non-ulcer dyspepsia, chronic intestinal pseudo-obstruction, functional dyspepsia, colonic pseudo-obstruction, duodenogastric reflux, gastro esophageal reflux disease, chronic idiopathic constipation, gastroparesis, heartburn, gastric cancer, and H. pylori infection. Likewise, the formulations which target to the ileum, terminal ileum, or ascending colon, are useful for the treatment or prevention of specific diseases and disorders, including one or more of the following: ileitis (e.g., post-operative ileitis), Crohn's disease, ulcerative colitis, terminal ileitis, and colon cancer.

The targeted release GCC formulations of the invention advantageously deliver the GCC agonist to the region of the gastrointestinal tract where it will have its greatest therapeutic effect. In a specific embodiment, the GCC agonist is formulated for specific delivery to the distal small intestines or to the large intestine, preferably the ileum, terminal ileum, or ascending colon. This formulation is particularly useful for the treatment of indications such as ulcerative colitis, in which the use of conventional oral formulations of GCC agonists is limited by the tendency to produce diarrhea. This adverse reaction is mitigated or eliminated by the targeted release formulations of the invention, particularly those that target release of the GCC agonist to the ileum, terminal ileum, or ascending colon.

Crohn's disease (CD) and ulcerative colitis (UC) are the principle syndromes encompassed by the classification of inflammatory bowel disease (IBD). While CD can affect any part of the gastrointestinal tract, it most commonly occurs in the distal ileum and colon, whereas UC by definition affects only the colon. In order to exert their anti-inflammatory therapeutic effects, orally administered GCC agonists must reach the inflamed sites in the distal ileum and colon. In accordance with one aspect of the invention, the GCC agonist is formulated for drug release at pH greater than 5.5 for the treatment of UC and CD. In one embodiment, the GCC agonist is formulated for targeted delivery to the ileum, preferably using a pH dependent release formulation for release at a pH above 5.5. pH dependent release formulations are described in more detail, infra, in Section 1.1. “Treatment” in this context refers to the effective induction and maintenance of remission. Thus, in one embodiment, the invention provides a method for the treatment of CD or UC which comprises administering to a subject in need thereof a therapeutically effective amount of a GCC agonist formulated for release at a pH above 5.5. It has recently been shown that gut pH in UC patients is generally more acidic as compared to healthy volunteers and it has also been postulated that these variations may affect pH mediated dissolution delivery of drug treatment (see Rubin, D. T. et al., Colonic pH differs depending on the activity of ulcerative colitis (UC): Report of two patients with pH measurements over time. Poster presented at the Annual Scientific Meeting of the American College of Gastroenterology, Oct. 23-28, 2009, San Diego, Calif., P1116). Further, the colonic pH rose substantially between active inflammation and subsequent clinical quiescence (see Rubin, D. T. et al., Luminal pH and transit time in patients with quiescent ulcerative colitis (US) resembles that of healthy controls. Poster presented at the Annual Scientific Meeting of the American College of Gastroenterology, Oct. 23-28, 2009, San Diego, Calif., P1114). Particularly in UC, some patients fail to achieve remission with standard outpatient therapy and this failure could possibly be due to the physiologic differences in lumenal transit time and pH. Thus, a further advantage of the present invention is to provide GCC agonist formulations specifically designed to deliver bioactive GCC agonists to the distal ileum or colon of affected patients by utilizing a pH dependent release formulation.

Another advantageous property of the targeted release formulations of the invention is that a lower effective dose of the GCC agonist is required to achieve the same therapeutic benefit as a GCC agonist whose release is not targeted. The targeted release of the GCC agonist further ensures that the agonist concentration is highest at its site of action, thus reducing the side effects that may be associated with oral administration.

In one embodiment, the GCC agonist formulation is an oral formulation optimized for delivery of a GCC agonist to the duodenum or jejunum. In a specific embodiment, this formulation comprises a core, which contains the GCC agonist, surrounded by one or more layers of a targeting material. The targeting material is chosen to provide targeted release of the GCC agonist to the duodenum or jejunum. In one embodiment, the formulation comprises an outer layer of targeting material which comprises a pH dependent polymer that is stable in the low pH environment of the stomach (pH 1-2) and begins to disintegrate in a pH range of from 4.5 to 5.5. This formulation protects the GCC agonists from the acidic environment of the stomach.

In another embodiment, the GCC agonist formulation is optimized for delivery of a GCC agonist to the ileum, terminal ileum, or ascending colon. In a specific embodiment, this formulation comprises a core, which contains the GCC agonist, surrounded by one or more layers of a targeting material. The targeting material is chosen to provide targeted release of the GCC agonist to the ileum, terminal ileum, or ascending colon. In one embodiment, the formulation comprises three layers of targeting material: (1) an outer layer which comprises a pH dependent polymer that is stable in the low pH environment of the stomach (pH 1-2) and begins to disintegrate in a pH range of from 6.5 to 7.5; (2) a middle layer which comprises a swellable polymer; and (3) an inner layer which comprises a pH dependent polymer that begins to disintegrate in a pH range of from 6.5 to 7.5. In a preferred embodiment, the pH dependent polymer is selected from among the EUDRAGIT polymers, for example, EUDRAGIT L, S, FS, and E polymers. In one embodiment, the swellable polymer is hydroxypropylmethylcellulose.

While any GCC agonist known in the art can be formulated according to the present invention, analogs of uroguanylin and bacterial ST peptides are preferred. In certain embodiments, the uroguanylin and bacterial ST peptide analogs have superior properties compared to naturally occurring, or “wild-type” peptides. For example, the uroguanylin and bacterial ST peptides for use in the present invention are preferably modified to increase their resistance to degradation at the N-terminus and C-terminus from carboxypeptidases, aminopeptidases, and/or by other proteolytic enzymes present in the stimulated human intestinal juices and human gastric juices. In certain embodiments, the GCC agonist formulation comprises a peptide consisting essentially of an amino acid sequence selected from SEQ ID NOs: 1-249. In a preferred embodiment, the peptide consists essentially of an amino acid sequence selected from SEQ ID NOs: 1, 8, 9, 55 and 56. The term “consists essentially of” refers to a peptide that is identical to the reference peptide in its amino acid sequence or to a peptide that does not differ substantially in terms of either structure or function from the reference peptide. A peptide differs substantially from the reference peptide if its primary amino acid sequence varies by more than three amino acids from the reference peptide or if its activation of cellular cGMP production is reduced by more than 50% compared to the reference peptide. Preferably, substantially similar peptides differ by no more than two amino acids and not by more than about 25% with respect to activating cGMP production. In preferred embodiments, the GCC agonist is a peptide comprising at least 12 amino acid residues, and most preferably comprising between 12 and 26 amino acids. Non-limiting examples of such analogs of uroguanylin and bacterial ST peptides are described in Section 1.1 below.

The invention provides methods for treating or preventing gastrointestinal disorders and increasing gastrointestinal motility in a subject in need thereof by administering an effective amount of a GCC agonist formulation to the subject. The term “treating” as used herein refers to a reduction, a partial improvement, amelioration, or a mitigation of at least one clinical symptom associated with the gastrointestinal disorders being treated. The term “preventing” refers to an inhibition or delay in the onset or progression of at least one clinical symptom associated with the gastrointestinal disorders to be prevented. The term “effective amount” as used herein refers to an amount that provides some improvement or benefit to the subject. In certain embodiments, an effective amount is an amount that provides some alleviation, mitigation, and/or decrease in at least one clinical symptom of the gastrointestinal disorder to be treated. In other embodiments, the effective amount is the amount that provides some inhibition or delay in the onset or progression of at least one clinical symptom associated with the gastrointestinal disorder to be prevented. The therapeutic effects need not be complete or curative, as long as some benefit is provided to the subject. The term “subject” preferably refers to a human subject but may also refer to a non-human primate or other mammal preferably selected from among a mouse, a rat, a dog, a cat, a cow, a horse, or a pig.

The gastointestinal disorders that can be treated or prevented according to the methods of the invention include, for example, irritable bowel syndrome (IBS), non-ulcer dyspepsia, chronic intestinal pseudo-obstruction, functional dyspepsia, colonic pseudo-obstruction, duodenogastric reflux, gastroesophageal reflux disease (GERD), ileus inflammation (e.g., post-operative ileus), gastroparesis, heartburn (high acidity in the GI tract), constipation (e.g., constipation associated with use of medications such as opioids, osteoarthritis drugs, and osteoporosis drugs), post surgical constipation, and constipation associated with neuropathic disorders.

In one embodiment, the GCC agonist formulation is optimized for delivery of a GCC agonist to the duodenum or jejunum. In accordance with this embodiment, the gastointestinal disorders that can be treated or prevented according to the methods of the invention are selected from the group consisting of irritable bowel syndrome (preferably constipation predominant), non-ulcer dyspepsia, chronic intestinal pseudo-obstruction, functional dyspepsia, colonic pseudo-obstruction, duodenogastric reflux, gastro esophageal reflux disease, chronic idiopathic constipation, gastroparesis, heartburn, gastric cancer, and H. pylori infection.

In another embodiment, the GCC agonist formulation is optimized for delivery of a GCC agonist to the ileum, terminal ileum, or ascending colon. In accordance with this embodiment, the gastointestinal disorders that can be treated or prevented according to the methods of the invention are selected from the group consisting of ileitis (e.g., post-operative ileitis), Crohn's disease, ulcerative colitis, terminal ileitis, and colon cancer.

The invention also provides methods for treating gastrointestinal cancer in a subject in need thereof by administering an effective amount of a GCC agonist formulation to the subject. The term “cancer” in this context includes tissue and organ carcinogenesis including metatases. In specific embodiments, the invention provides methods for treating a gastrointestinal cancer selected from among gastric cancer, esophageal cancer, pancreatic cancer, colorectal cancer, intestinal cancer, anal cancer, liver cancer, gallbladder cancer, or colon cancer.

In accordance with the methods of the present invention, the GCC agonist formulation can be administered alone or in combination with one or more additional therapeutic agents to prevent or treat inflammation, cancer and other disorders, particularly of the gastrointestinal tract. In one embodiment, the GCC agonist formulation is administered in combination with one or more additional therapeutic agents selected from the group consisting of phosphodiesterase inhibitors, cyclic nucleotides (such as cGMP and cAMP), a laxative (such as SENNA, METAMUCIL, MIRALAX, PEG, or calcium polycarbophil), a stool softener, an anti-tumor necrosis factor alpha therapy for IBD (such as REMICADE, ENBREL, or HUMAIRA), and anti-inflammatory drugs (such as COX-2 inhibitors, sulfasalazine, 5-ASA derivatives and NSAIDS). In certain embodiments, the GCC agonist formulation is administered in combination with an effective dose of an inhibitor of cGMP-specific phosphodiesterase (cGMP-PDE) either concurrently or sequentially with said GCC agonist. cGMP-PDE inhibitors include, for example, suldinac sulfone, zaprinast, motapizone, vardenifil, and sildenafil. In another embodiment, the GCC agonist formulation is administered in combination with inhibitors of cyclic nucleotide transporters.

1.1 Formulations

The formulations of the invention are optimized for delivery of a GCC agonist to a specific region of the gastrointestinal tract. In a preferred embodiment, the formulations are oral formulations. The formulations of the invention comprise a core, which contains the GCC agonist, and one or more targeting materials which may form one or more layers around the core, or which may be formed in a matrix with the core. The targeting material is chosen to target the release of the GCC agonist to a specific region of the gastrointestinal tract. The targeting material preferably comprises one of the following: (1) a pH dependent polymer; (2) a swellable polymer; or (3) a degradable composition. Targeting materials are further described in Sections 1.1.1 to 1.1.3 below.

In one embodiment, the targeting material is chosen to provide for the pH-dependent release of the GCC agonist. In a preferred embodiment, the targeting material for a pH-dependent release formulation comprises a pH-dependent polymer that is stable in the low pH environment of the stomach (i.e., at pH 1-2) and begins to disintegrate at the pH of the proximal small intestine (pH 4.5-6) or distal ileum (pH 7-8). Preferably, the pH-dependent polymer is a methacrylic acid copolymer selected from among the EUDRAGIT polymers, which are further described below in Section 1.1.1.

In one embodiment, the targeting material is chosen to provide for a controlled (time-dependent) release of the GCC agonist. In a preferred embodiment, the targeting material for a controlled release formulation comprises at least one swellable polymer, as further described below in Section 1.1.2.

In another embodiment, the targeting material for a controlled release formulation comprises a degradable compostion such as a natural or synthetic polymer which is susceptibile to being degraded by at least one colonic bacterial enzyme. Preferably, the GCC agonist is embedded in the polymer matrix.

In another embodiment, the targeting material for a controlled release formulation comprises a degradable composition in the form of a carrier molecule covalently conjugated to the GCC agonist by a labile bond which is stable in the stomach and small intestine but which degrades in the lower gastrointestinal tract, especially the colon, thereby providing for the targeted release of the GCC agonist. A GCC agonist covalently conjugated to a carrier in this manner is referred to herein as a GCC “prodrug.” The formulations comprising a GCC prodrug are further described below in Section 1.1.3.

In certain embodiments, the formulation is optimized for delivery of a GCC agonist to the duodenum or jejunum. In one embodiment, the formulation optimized for delivery of a GCC agonist to the duodenum or jejunum comprises a core, which contains the GCC agonist, surrounded by a targeting layer comprised of a pH dependent polymer which degrades in a pH range of 4.5 to 5.5. Preferably the pH dependent polymer is a methacrylic acid copolymer selected from among the EUDRAGIT polymers.

In certain embodiments, the formulation is optimized for delivery of a GCC agonist to the ileum, terminal ileum, or ascending colon. In one embodiment, the formulation optimized for delivery of a GCC agonist to the ileum, terminal ileum, or ascending colon comprises a core, which contains the GCC agonist, surrounded by one, two, three, or more layers of targeting materials. At least one targeting material comprises a pH dependent polymer which degrades in a pH range of 6.5 to 7.5. Preferably the pH dependent polymer is a methacrylic acid copolymer selected from among the EUDRAGIT polymers. Where there is more than one layer of targeting materials surrounding the core, at least one layer comprises a swellable polymer. Preferably, the swellable polymer is an acrylic copolymer, polyvinylacetate, or a cellulose derivative. In one embodiment, the swellable polymer is an acrylic copolymer selected from EUDRAGIT RL, EUDRAGIT RS, and EUDRAGIT NE. In another embodiment, the swellable polymer is a cellulose derivative selected from ethylcellulose, cellulose acetate, hydroxypropylcellulose, hydroxypropylmethylcellulose, hydroxyethylcellulose, methylcellulose, carboxymethylcellulose, and metal salts of carboxymethylcellulose. In another embodiment, the formulation comprises EUDRACOL, which combines both pH- and time-dependent EUDRAGIT polymers. EUDRAGIT polymers are described below in Sections 1.1.1 and 1.1.2. Further examples of swellable polymers are described below in Section 1.1.2.

In accordance with the invention, the enteric coating chosen for the formulation is any coating which will achieve the targeting objective of the formulation. Examples of suitable enteric coatings include, but are not limited to, the following: (1) acrylic polymers (anionic polymers of methacrylic acid and methacrylates polymers with methacrylic acid as a functional group) such as the EUDRAGIT (Degussa) polymers, e.g., for release in the duodenum (dissolution above pH 5.5), EUDRAGIT L 100-55 and EUDRAGIT L 30 D-55; for release in the jejunum (dissolution above pH 6.0), EUDRAGIT L 100; for release in the ileum (dissolution above pH 7), EUDRAGIT S 100 and EUDRAGIT FS 30, and COLORCON ACRYL-EZE; (2) polyvinyl Acetate Phthalate (PVAP) including the COLORCON SURETERIC Aqueous Enteric Coating System, and the COLORCON OPADRY Enteric Coating System; (3) hypromellose Phthalate, NF (Hydroxy Propyl Methyl Cellulose Phthalate; HPMCP; HP-55 Shin-Etsu); (4) cellulose acetate phthalate (CAP), such as AQUACOAT CPD; and (5) cellulose acetate trimellitate (CAT). Further examples of suitable enteric coatings include, without limitation, sustained release blends such as EUDRACOL, EUDRAPULSE, and EUDRAMODE, as well as sustained release polymers such as the EUDRAGIT RL, RS, and NE polymers.

The GCC agonist-containing core of a formulation of the invention can be in the form of a tablet, a capsule, granules, pellets, or crystals. In certain embodiments, the core comprises microparticles or microspheres. In one embodiment, the core comprises a cellulose acetate butyrate microsphere. In some embodiments, the core is coated with one or more layers of targeting materials. In other embodiments, the core is formulated in a matrix with a targeting material. In certain embodiments, the core matrix is coated with at least one additional targeting material.

The GCC-agonist containing core of the present formulations is formed according to art-recognized methods. In one embodiment, the core is formed with a pellet-forming agent such as microcrystalline cellulose, low-substituted hydroxypropylcellulose, chitin, chitosan, or any combination or mixture thereof. Generally, an amount of pellet-forming agent that is less than 20% by weight results in poor sphericity and broad particle size distribution. Accordingly, the pellet-forming agent of the present formulations is preferably at least 20% by weight. In certain embodiments, the pellet-forming agent is present at 20% to 95% or 50% to 90% by weight.

The GCC agonist formulation may further comprise one or more pharmaceutically acceptable excipients. The excipients may comprise part of the core or part of one or more outer layers surrounding the core. Preferably, the excipients are present in an amount of 2 to 70% or 5 to 50% by weight. The term excipient broadly refers to a biologically inactive substance used in combination with the active agents of the formulation. An excipient can be used, for example, as a solubilizing agent, a stabilizing agent, a diluent, an inert carrier, a preservative, a binder, a disintegrant, a coating agent, a flavoring agent, or a coloring agent. Preferably, at least one excipient is chosen to provide one or more beneficial physical properties to the formulation, such as increased stability and/or solubility of the active agent(s).

A “pharmaceutically acceptable” excipient is one that has been approved by a state or federal regulatory agency for use in animals, and preferably for use in humans, or is listed in the U.S. Pharmacopia, the European Pharmacopia or another generally recognized pharmacopia for use in animals, and preferably for use in humans. Examples of excipients include certain inert proteins such as albumins; hydrophilic polymers such as polyvinylpyrrolidone; amino acids such as aspartic acid (which may alternatively be referred to as aspartate), glutamic acid (which may alternatively be referred to as glutamate), lysine, arginine, glycine, and histidine; fatty acids and phospholipids such as alkyl sulfonates and caprylate; surfactants such as sodium dodecyl sulphate and polysorbate; nonionic surfactants such as such as TWEEN®, PLURONICS®, or polyethylene glycol (PEG); carbohydrates such as glucose, sucrose, mannose, maltose, trehalose, and dextrins, including cyclodextrins; polyols such as sorbitol; chelating agents such as EDTA; and salt-forming counter-ions such as sodium. Particularly preferred are hydrophilic excipients which reduce the protein binding activity and aggregation of GCC agonist peptides.

In some embodiments, the GCC agonist formulation further comprises one or more excipients selected from among an absorption enhancer, a binder, a disintegrant, and a hardness enhancing agent. In other embodiments, the formulation further comprises one or more excipients selected from among a wicking agent, a stabilizer, a flow regulating agent, a lubricant, an antioxidant, a chelating agent, or a sequestrate.

Non-limiting examples of suitable binders include starch, polyvinylpyrrolidone (POVIDONE), low molecular weight hydroxypropylcellulose, low molecular weight hydroxypropylmethylcellulose, low molecular weight carboxymethylcellulose, ethylcellulose, gelatin, polyethylene oxide, acacia, dextrin, magnesium aluminum silicate, and polymethacrylates. Non-limiting examples of a disintegrant include croscarmellose sodium crospovidone (cross-linked PVP), sodium carboxymethyl starch (sodium starch glycolate), pregelatinized starch (starch 1500), microcrystalline starch, water insoluble starch, calcium carboxymethyl cellulose, and magnesium aluminum silicate (Veegum). In certain embodiments, a binder is selected from polyvinylpyrrolidone and sodium carboxymethylcellulose.

Non-limiting examples of a wicking agent include colloidal silicon dioxide, kaolin, titanium oxide, fumed silicon dioxide, alumina, niacinamide, sodium lauryl sulfate, low molecular weight polyvinyl pyrrolidone, m-pyrol, bentonite, magnesium aluminum silicate, polyester, polyethylene, and mixtures thereof. In certain embodiments, a wicking agent is selected from sodium lauryl sulfate, colloidal silicon dioxide, and low molecular weight polyvinyl pyrrolidone.

Non-limiting examples of a stabilizer include butyl hydroxyanisole, ascorbic acid, citric acid, and mixtures thereof. Preferably, the stabilizer is a basic substance which can elevate the pH of an aqueous solution or dispersion of the formulation to at least about pH 6.8. Examples of such basic substances include, for example, antacids such as magnesium aluminometasilicate, magnesium aluminosilicate, magnesium aluminate, dried aluminum hydroxide, synthetic hydrotalcite, synthetic aluminum silicate, magnesium carbonate, precipitated calcium carbonate, magnesium oxide, aluminum hydroxide, and sodium hydrogencarbonate. Other examples include pH-regulating agents such as L-arginine, sodium phosphate, disodium hydrogen phosphate, sodium dihydrogenphosphate, potassium phosphate, dipotassium hydrogenphosphate, potassium dihydrogenphosphate, disodium citrate, sodium succinate, ammonium chloride, and sodium benzoate. In certain embodiments, a stabilizer is selected from ascorbic acid and magnesium aluminometasilicate.

In an embodiment where the stabilizer is a basic substance, the basic substance can be an inorganic water-soluble compound or a inorganic water-insoluble compound. Non-limiting examples of an inorganic water-soluble compounds for use as a stabilizer include carbonate salts such as sodium carbonate, potassium carbonate, sodium bicarbonate, or potassium hydrogen carbonate; phosphate salts such as anhydrous sodium phosphate, potassium phosphate, calcium dibasic phosphate, or trisodium phosphate; and alkali metal hydroxides, such as sodium, potassium, or lithium hydroxide. Non-limiting examples of inorganic water-insoluble compounds for use as a stabilizer include suitable alkaline compounds capable of imparting the requisite basicity, such as those commonly employed in antiacid compositions, for example, magnesium oxide, magnesium hydroxide, magnesium carbonate, magnesium hydrogen carbonate, aluminum hydroxide, calcium hydroxide, or calcium carbonate; composite aluminum-magnesium compounds, such as magnesium aluminum hydroxide; silicate compounds such as magnesium aluminum silicate (Veegum F), magnesium aluminometasilicate (Nesulin FH2), magnesium aluminosilicate (Nisulin A); and pharmaceutically acceptable salts of phosphoric acid such as tribasic calcium phosphate.

Non-limiting examples of a flow regulating agents include a colloidal silicon dioxide and aluminum silicate.

Non-limiting examples of a lubricant include stearate salts, such as magnesium stearate, calcium stearate, and sodium stearate, stearic acid, talc, sodium stearyl fumarate, sodium lauryl sulfate, sodium benzoate, polyethylene glycol, polyvinyl alcohol, glycerol behenate compritol (glycerol behenate), corola oil, glyceryl palmitostearate, hydrogenated vegetable oil, magnesium oxide, mineral oil, poloxamer, and combinations thereof. In certain embodiments, a lubricant is selected from talc and magnesium stearate.

Non-limiting examples of antioxidants include 4,4 (2,3 dimethyl tetramethylene dipyrochatechol), tocopherol-rich extract (natural vitamin E), α-tocopherol (synthetic Vitamin E), β-tocopherol, γ-tocopherol, δ-tocopherol, butylhydroxinon, butyl hydroxyanisole (BHA), butyl hydroxytoluene (BHT), propyl gallate, octyl gallate, dodecyl gallate, tertiary butylhydroquinone (TBHQ), fumaric acid, malic acid, ascorbic acid (Vitamin C), sodium ascorbate, calcium ascorbate, potassium ascorbate, ascorbyl palmitate, ascorbyl stearate, citric acid, sodium lactate, potassium lactate, calcium lactate, magnesium lactate, anoxomer, erythorbic acid, sodium erythorbate, erythorbin acid, sodium erythorbin, ethoxyquin, glycine, gum guaiac, sodium citrates (monosodium citrate, disodium citrate, trisodium citrate), potassium citrates (monopotassium citrate, tripotassium citrate), lecithin, polyphosphate, tartaric acid, sodium tartrates (monosodium tartrate, disodium tartrate), potassium tartrates (monopotassium tartrate, dipotassium tartrate), sodium potassium tartrate, phosphoric acid, sodium phosphates (monosodium phosphate, disodium phosphate, trisodium phosphate), potassium phosphates (monopotassium phosphate, dipotassium phosphate, tripotassium phosphate), calcium disodium ethylene diamine tetra-acetate (Calcium disodium EDTA), lactic acid, trihydroxy butyrophenone and thiodipropionic acid.

In certain embodiments, the core of the formulation comprises an antioxidant and both a chelator and a sequestrate. The chelating agent acts to remove trace quantities of metals which might otherwise bind to the GCC agonist and cause loss of activity, for example through oxidation. The sequestrate preferably has several hydroxyl and/or carboxylic acid groups which provide a supply of hydrogen for regeneration of the inactivated antioxidant free radical. Non-limiting examples of chelating agents include antioxidants, dipotassium edentate, disodium edentate, edetate calcium disodium, edetic acid, fumaric acid, malic acid, maltol, sodium edentate, and trisodium edetate. Non-limiting examples of sequestrates include citric acid and ascorbic acid.

In some embodiments, the formulation further comprises a filler. Preferably, the filler is present in an amount of from 10% to 85% by weight. Non-limiting examples of suitable materials for use as a filler include starch, lactitol, lactose, an inorganic calcium salt, microcrystalline cellulose, sucrose, and combinations thereof. In some embodiments, the filler comprises microcrystalline cellulose. Preferably, the microcrystalline cellulose has a particle size of less than about 100 microns, and most preferably the microcrystalline cellulose has a particle size of about 50 microns.

In some embodiments, the core optionally includes a buffering agent such as an inorganic salt compound and an organic alkaline salt compound. Non-limiting examples of a buffering agent include potassium bicarbonate, potassium citrate, potassium hydroxide, sodium bicarbonate, sodium citrate, sodium hydroxide, calcium carbonate, dibasic sodium phosphate, monosodium glutamate, tribasic calcium phosphate, monoethanolamine, diethanolamine, triethanolamine, citric acid monohydrate, lactic acid, propionic acid, tartaric acid, fumaric acid, malic acid, and monobasic sodium phosphate.

In some embodiments, the core further comprises a preservative. Non-limiting examples of a preservative include an antioxidant, dipotassium edentate, disodium edentate, edetate calcium disodium, edetic acid, fumaric acid, malic acid, maltol, sodium edentate, and trisodium edentate.

The GCC agonist formulations of the invention are preferably optimized for oral delivery. However, in some embodiments, the formulations may be prepared in the form of suppositories (e.g., with conventional suppository bases such as cocoa butter and other glycerides) or retention enemas for rectal delivery. Solid oral dosage forms may optionally be treated with coating systems (e.g. Opadry® fx film coating system, for example Opadry® blue (OY-LS-20921), Opadry® white (YS-2-7063), Opadry® white (YS-1-7040), and black ink (S-1-8 106).

1.1.1 pH Dependent Release Formulations

In certain embodiments, the formulations of the invention comprise a pH-dependent targeting material that is pharmacologically inactive, meaning that it is excreted without being absorbed or metabolized. In some embodiments, the GCC agonist-loaded core is coated with a pH-dependent material. In other embodiments, the pH-dependent material comprises part of an outer layer which surrounds the core, for example in certain embodiments of a controlled (time-dependent) release formulation. In some embodiments, the GCC agonist-loaded core is formed as a matrix with a pH-dependent material. Preferably, the pH-dependent material comprises a pH-dependent polymer.

Preferably, the pH-dependent polymer is stable in the low pH environment of the stomach (i.e., at pH 1-2) and begins to disintegrate at the higher pH of the small intestine (pH 6-7) or distal ileum (pH 7-8). In certain embodiments, the polymer begins to disintegrate at pH 4.5-4.8, pH 4.8-5.0, pH 5.0-5.2, pH 5.2-5.4, pH 5.4-5.8, pH 5.8-6.0, pH 6.0-6.2, pH 6.2-6.4, pH 6.4-6.6, pH 6.6-6.8, pH 6.8-7.0, pH 7.0-7.2, or pH 7.2-7.4. In certain embodiments, the polymer begins to disintegrate at pH 4.5-5.5, pH 5.5-6.5, or pH 6.5-7.5. The pH at which a pH-sensitive polymer begins to disintegrate is also referred to herein as the “threshold pH” of the polymer.

In certain embodiments, the pH-dependent polymer is a methacrylic acid copolymer, a polyvinyl acetate phthalate, a hydroxypropylmethylcellulose phthalate, a cellulose acetate trimelliate, a cellulose acetate phthalate, or a hydroxypropyl methyl cellulose acetate succinate.

In a preferred embodiment, the pH-dependent polymer is a methacrylic acid copolymer selected from among the EUDRAGIT polymers. EUDRAGIT polymers are available in a wide range of different concentrations and physical forms, including aqueous solutions, aqueous dispersion, organic solutions, and solid substances. The pharmaceutical properties of the polymers are determined by the chemical properties of their functional groups. For example, EUDRAGIT L, S, FS and E polymers have acidic or alkaline groups that are pH-dependent. Enteric EUDRAGIT coatings provide protection against release of the GCC agonist in the stomach and enable controlled release in the intestine. In certain embodiments, anionic EUDRAGIT grades containing carboxyl groups are mixed with each other to provide pH-dependent release of the GCC agonist. In certain embodiments, EUDRAGIT L and S grades are used for enteric coatings. In one embodiment, EUDRAGIT FS 30D is used for controlled release in the colon. The various EUDRAGIT polymers are further described in international pharmacopeias such as Ph. Eur., USP/NF, DMF and JPE.

In specific embodiments, the pH-dependent polymer is a methacrylic acid copolymer selected from EUDRAGIT L100, having a threshold pH of 6.0; EUDRAGIT S100, having a threshold pH of 7.0; EUDRAGIT L-30D, having a threshold pH of 5.6; EUDRAGIT FS 30D, having a threshold pH of 6.8; or EUDRAGIT L100-55, having a threshold pH of 5.5, or a combination thereof.

1.1.2 Controlled Release Formulations

In one embodiment, the GCC agonist formulation comprises a targeting material which provides a controlled (time-dependent) release of the GCC agonist. Controlled release in this context includes delayed sustained release, delayed controlled release, delayed slow release, delayed prolonged release, delayed extended release, and a sudden release or “burst.”

Preferably, the controlled release formulation comprises a slowly disintegrating core comprising the GCC agonist surrounded by the targeting material. The targeting material preferably comprises at least one swellable polymer. Non-limiting examples of swellable polymers for use in a controlled release formulation of the invention include acrylic copolymers, e.g., EUDRAGIT RL, EUDRAGIT RS, or EUDRAGIT NE; polyvinylacetate, e.g., KOLLICOAT SR 30D; and cellulose derivatives such as ethylcellulose or cellulose acetate, e.g., SURELEASE and AQUACOAT ECD. In a preferred embodiment, the targeting material comprises one or more of EUDRAGIT RL, EUDRAGIT RS, or EUDRAGIT NE to provide controlled time release of the GCC agonist by pH-independent swelling. In a particular embodiment, the targeting material comprises EUDRAGIT RL:RS (2:8) and an outing coating comprising EUDRAGIT FS.

Further non-limiting examples of swellable polymers that can be used in the sustained release formulations of the invention include poly(hydroxyalkyl methacrylate) having a molecular weight of from 30,000 to 5,000,000; kappa-carrageenan; polyvinylpyrrolidone having a molecular weight of from 10,000 to 360,000; anionic and cationic hydrogels; polyelectrolyte complexes; poly(vinyl alcohol) having low amounts of acetate, cross-linked with glyoxal, formaldehyde, or glutaraldehyde and having a degree of polymerization from 200 to 30,000; a mixture comprising methyl cellulose, cross-linked agar and carboxymethyl cellulose; a water-insoluble, water-swellable copolymer produced by forming a dispersion of finely divided maleic anhydride with styrene, ethylene, propylene, butylene or isobutylene; water-swellable polymers of N-vinyl lactams; polysaccharide, water swellable gums, high viscosity hydroxylpropylmethyl cellulose and/or mixtures thereof. In certain embodiments, the swellable polymer is selected from the group consisting of calcium pectinate, cross-linked polysaccharide, water insoluble starch, microcrystalline cellulose, water insoluble cross-linked peptide, water insoluble cross-linked protein, water insoluble cross-linked gelatin, water insoluble cross-linked hydrolyzed gelatin, water insoluble cross-linked collagen, modified cellulose, and cross-linked polyacrylic acid. Non-limiting examples of a cross-linked polysaccharide include insoluble metal salts or cross-linked derivatives of alginate, pectin, xantham gum, guar gum, tragacanth gum, and locust bean gum, carrageenan, metal salts thereof, and covalently cross-linked derivatives thereof. Non-limiting examples of modified cellulose include cross-linked derivatives of hydroxypropylcellulose, hydroxypropylmethylcellulose, hydroxyethylcellulose, methylcellulose, carboxymethylcellulose, and metal salts of carboxymethylcellulose.

In certain embodiments, the swellable core also comprises a wicking agent such as silicon dioxide. The wicking agent may also be selected from a disintegrant such as microcrystalline cellulose to enhance the speed of water uptake. Other suitable wicking agents include, but are not limited to, kaolin, titanium dioxide, fumed silicon dioxide, alumina, niacinamide, sodium lauryl sulfate, low molecular weight polyvinyl pyrrolidone, m-pyrol, bentonite, magnesium aluminum silicate, polyester, polyethylene, and mixtures thereof.

In certain embodiments, the targeting material, which may comprise part of the core and/or form one or more layers coating the core, optionally further comprises at least one of a lubricant, a flow promoting agent, a plasticizer, an anti-sticking agent, surfactant, wetting agent, suspending agent and dispersing agent.

In certain embodiments, the targeting material comprises a water insoluble polymer and a pore-forming agent. Non-limiting examples of pore forming agents include saccharose, sodium chloride, potassium chloride, polyvinylpyrrolidone, and/or polyethyleneglycol, water soluble organic acids, sugars and sugar alcohol. In certain embodiments, the pore forming agent forms part of an outer layer or coating. In other embodiments, the pore forming agent is distributed uniformly throughout the water insoluble polymer.

In one embodiment, the targeting material comprises a compression coating. Non-limiting examples of materials that can be used as a compression coating include a gum selected from the group consisting of xanthan gum, locust bean gum, galactans, mannans, alginates, gum karaya, pectin, agar, tragacanth, accacia, carrageenan, tragacanth, chitosan, agar, alginic acid, hydrocolloids acacia catechu, salai guggal, indian bodellum, copaiba gum, asafetida, cambi gum, Enterolobium cyclocarpum, mastic gum, benzoin gum, sandarac, gambier gum, butea frondosa (Flame of Forest Gum), myrrh, konjak mannan, guar gum, welan gum, gellan gum, tara gum, locust bean gum, carageenan gum, glucomannan, galactan gum, sodium alginate, tragacanth, chitosan, xanthan gum, deacetylated xanthan gum, pectin, sodium polypectate, gluten, karaya gum, tamarind gum, ghatti gum, Accaroid/Yacca/Red gum, dammar gum, juniper gum, ester gum, ipil-ipil seed gum, gum talha (acacia seyal), and cultured plant cell gums including those of the plants of the genera: acacia, actinidia, aptenia, carbobrotus, chickorium, cucumis, glycine, hibiscus, hordeum, letuca, lycopersicon, malus, medicago, mesembryanthemum, oryza, panicum, phalaris, phleum, poliathus, polycarbophil, sida, solanum, trifolium, trigonella, Afzelia africana seed gum, Treculia africana gum, detarium gum, cassia gum, carob gum, Prosopis africana gum, Colocassia esulenta gum, Hakea gibbosa gum, khaya gum, scleroglucan, and zea, as well as mixtures of any of the foregoing.

In some embodiments, the targeting material further comprises a plasticizer, a stiffening agent, a wetting agent, a suspending agent, or a dispersing agent, or a combination thereof. Non-limiting examples of a plasticizer include dibutyl sebacate, polyethylene glycol and polypropylene glycol, dibutyl phthalate, diethyl phthalate, triethyl citrate, tributyl citrate, acetylated monoglyceride, acetyl tributyl citrate, triacetin, dimethyl phthalate, benzyl benzoate, butyl and/or glycol esters of fatty acids, refined mineral oils, oleic acid, castor oil, corn oil, camphor, glycerol and sorbitol or a combination thereof. In one embodiment, the stiffening agent comprises cetyl alcohol. Non-limiting examples of wetting agents include a poloxamer, polyoxyethylene ethers, polyoxyethylene sorbitan fatty acid esters, polyoxymethylene stearate, sodium lauryl sulfate, sorbitan fatty acid esters, benzalkonium chloride, polyethoxylated castor oil, and docusate sodium. Non-limiting examples of suspending agents include alginic acid, bentonite, carbomer, carboxymethylcellulose, carboxymethylcellulose calcium, hydroxyethylcellulose, hydroxypropylcellulose, microcrystalline cellulose, colloidal silicon dioxide, dextrin, gelatin, guar gum, xanthan gum, kaolin, magnesium aluminum silicate, maltitol, medium chain triglycerides, methylcellulose, polyoxyethylene sorbitan fatty acid esters, polyvinylpyrrolidinone, propylene glycol alginate, sodium alginate, sorbitan fatty acid esters, and tragacanth. Non-limiting examples of dispersing agents include poloxamer, polyoxyethylene sorbitan fatty acid esters and sorbitan fatty acid esters.

In certain embodiments, the targeted release formulation further comprises an outer enteric coating over the targeted release material. Preferably, the enteric coating is selected from the group consisting of cellulose acetate phthalate, hydroxy propyl methyl cellulose acetate succinate, EUDRAGIT L100 and EUDRAGIT L30D-55.

1.1.2.1 Burst Formulation

In one embodiment, the GCC agonist formulation is a time-delayed formulation designed to release the GCC agonist in a fast burst in the colon or small intestine (“burst formulation”). The formulation comprises a core and an outer layer. The core comprises at least one GCC agonist and at least one burst controlling agent. In certain embodiments, the core further comprises at least one disintegrant selected from the group consisting of croscarmellose sodium, crospovidone (cross-linked PVP), sodium carboxymethyl starch (sodium starch glycolate), cross-linked sodium carboxymethyl cellulose (Croscarmellose), pregelatinized starch (starch 1500), microcrystalline starch, water insoluble starch, calcium carboxymethyl cellulose, and magnesium aluminum silicate, or a combination thereof. In other embodiments, the core further comprises at least one of an absorption enhancer, a binder, a hardness enhancing agent, a buffering agent, a filler, a flow regulating agent, a lubricant, a synergistic agent, a chelator, an antioxidant, a stabilizer and a preservative. Optionally, the core also comprises one or more other excipients.

The burst controlling agent in the core preferably comprises a water insoluble polymer for controlling the rate of penetration of water into the core and raising the internal pressure (osmotic pressure) inside the core. Such a burst controlling agent is preferably able to swell upon contact with liquid. Non-limiting examples of suitable water insoluble polymers include cross-linked polysaccharide, water insoluble starch, microcrystalline cellulose, water insoluble cross-linked peptide, water insoluble cross-linked protein, water insoluble cross-linked gelatin, water insoluble cross-linked hydrolyzed gelatin, water insoluble cross-linked collagen modified cellulose, and cross-linked polyacrylic acid. In one embodiment, the water insoluble polymer is a cross-linked polysaccharide selected from the group consisting of insoluble metal salts or cross-linked derivatives of alginate, pectin, xanthan gum, guar gum, tragacanth gum, and locust bean gum, carrageenan, metal salts thereof, and covalently cross-linked derivatives thereof. In one embodiment, the water insoluble polymer is a modified cellulose selected from the group consisting of cross-linked derivatives of hydroxypropylcellulose, hydroxypropylmethylcellulose, hydroxyethylcellulose, methylcellulose, carboxymethylcellulose, and metal salts of carboxymethylcellulose. In another embodiment, the water insoluble polymer is selected from calcium pectinate, microcrystalline cellulose, or a combination thereof.

The outer layer comprises a water insoluble hydrophobic carrier and a pore forming agent comprised of a water insoluble hydrophilic particular matter. The pore forming agent is a water permeable agent which allows entry of liquid into the core. Optionally, the outer layer further comprises at least one of a wetting agent, a suspending agent, a dispersing agent, a stiffening agent, and a plasticizer.

In certain embodiments, the water insoluble hydrophobic carrier is selected from the group consisting of a dimethylaminoethylacrylate/ethylmethacrylate copolymer, the copolymer being based on acrylic and methacrylic acid esters with a low content of quaternary ammonium groups, wherein the molar ratio of the ammonium groups to the remaining neutral (meth)acrylic acid esters is approximately 1:20, the polymer corresponding to USP/NF “Ammonio Methacrylate Copolymer Type A”, an ethylmethacrylate/chlorotrimethylammoniumethyl methacrylate copolymer, the copolymer based on acrylic and methacrylic acid esters with a low content of quaternary ammonium groups wherein the molar ratio of the ammonium groups to the remaining neutral (meth)acrylic acid esters is 1:40, the polymer corresponding to USP/NF “Ammonio Methacrylate Copolymer Type B”, a dimethylaminoethylmethacrylate/methylmethacrylate and butylmethacrylate copolymer, a copolymer based on neutral methacrylic acid esters and dimethylaminoethyl methacrylate esters wherein the polymer is cationic in the presence of acids, an ethylacrylate and methylacrylate/ethylmethacrylate and methyl methylacrylate copolymer, the copolymer being a neutral copolymer based on neutral methacrylic acid and acrylic acid esters, ethylcellulose, shellac, zein, and waxes.

In certain embodiments, the water insoluble particulate matter is a hydrophilic yet water insoluble polymer, preferably selected from the group consisting of a water insoluble cross-linked polysaccharide, a water insoluble cross-linked protein, a water insoluble cross-linked peptide, water insoluble cross-linked gelatin, water insoluble cross-linked hydrolyzed gelatin, water insoluble cross-linked collagen, water insoluble cross linked polyacrylic acid, water insoluble cross-linked cellulose derivatives, water insoluble cross-linked polyvinyl pyrrolidone, micro crystalline cellulose, insoluble starch, micro crystalline starch and a combination thereof. Most preferably, the water insoluble particulate matter is microcrystalline cellulose.

In certain embodiments, the burst formulation further comprises an enteric coating on the outer layer. The enteric coating is preferably selected from the group consisting of cellulose acetate phthalate, hydroxy propyl methyl cellulose acetate succinate, and a EUDRAGIT polymer such as EUDRAGIT L100 or EUDRAGIT L30D-55.

1.1.3 Biodegradable Formulations

In one embodiment, the GCC agonist formulation comprises a natural or synthetic polymer which is susceptible to being degraded by at least one colonic bacterial enzyme. Preferably, the GCC agonist is embedded in the polymer matrix. Non-limiting examples of such polymers include polymers of polysaccharides such as amylase, chitosan, chondroitin sulfate, cyclodextrin, dextran, guar gum, pectin, and xylan. Preferably, the natural or synthetic polymer is gelled or crosslinked with a cation such as a zinc cation, for example from zinc sulfate, zinc chloride, or zinc acetate. The formulation is preferably in the form of ionically crosslinked beads which are subsequently coated with an enteric coating. The enteric coating can comprise any suitable enteric coating material, such as hydroxypropylmethyl cellulose phthalate, polyvinyl acetate phthalate, cellulose acetate phthalate, hydroxypropylmethyl cellulose acetate succinate, alginic acid, and sodium alginate, or a EUDRAGIT polymer.

In another embodiment, the GCC agonist formulation comprises a GCC agonist covalently conjugated to a carrier molecule such that the covalent bond between the GCC agonist and the carrier is stable in the stomach and small intestine but labile in the lower gastrointestinal tract, especially the colon. The GCC agonist covalently linked to a carrier molecule is referred to as the “GCC prodrug.” In certain embodiments, the GCC prodrug comprises a GCC agonist covalently conjugated to a carrier molecule via an azo bond or a glycosidic bond. In other embodiments, the GCC prodrug comprises a glucuronide, a cyclodextrin, a dextran ester, or a polar amino acid. In certain embodiments, the GCC prodrug is a polymeric prodrug. In one embodiment, the polymeric prodrug comprises polyamides containing azo groups.

1.2 GCC Agonists

The GCC agonists for use in the formulations and methods of the invention bind to guanylate cyclase C and stimulate intracellular production of cGMP. Optionally, the GCC agonists induce apoptosis and inhibit proliferation of epithelial cells. The term, “guanylate cyclase C” refers to a transmembrane form of guanylate cyclase that acts as the intestinal receptor for the heat-stable toxin (ST) peptides secreted by enteric bacteria. Guanylate cyclase C is also the receptor for the naturally occurring peptides guanylin and uroguanylin. The possibility that there may be different receptors for each of these peptides has not been excluded. Hence, the term “guanylate cyclase C” may also encompass a class of transmembrane guanylate cyclase receptors expressed on epithelial cells lining the gastrointestinal mucosa.

The term “GCC agonist” refers to both peptides and non-peptide compounds such as that bind to an intestinal guanylate cyclase C and stimulate the intracellular production of cGMP. Where the GCC agonist is a peptide, the term encompasses biologically active fragments of such peptides and pro-peptides that bind to guanylate cyclase C and stimulate the intracellular production of cGMP.

Preferably, the GCC agonists for use in the formulations and methods of the invention stimulate intracellular cGMP production at higher levels than naturally occurring GCC agonists such as uroguanylin, guanylin, and ST peptides. In some embodiments, the GCC agonists stimulate intracellular cGMP production at higher levels than the peptide designated SP-304 (SEQ ID NO:1). In specific embodiments, a GCC agonist for use in the formulations and methods of the invention stimulates 5%, 10%, 20%, 30%, 40%, 50%, 75%, 90% or more intracellular cGMP compared to uroguanylin, guanylin, lymphoguanylin, linaclotide, ST peptides, or SP-304. The terms “induce” and “stimulate” are used interchangeably throughout the specification.

Preferably, the GCC agonists for use in the formulations and methods of the invention are more stable than naturally occurring GCC agonists such as uroguanylin, guanylin, and ST peptides. In some embodiments, the GCC agonists are more stable than the peptide designated SP-304. “Stability” in this context refers to resistance to degradation in gastrointestinal fluid and/or intestinal fluid (or simulated gastrointestinal or intestinal fluids) compared to the reference peptide. For example, the GCC agonists for use in the formulations and methods of the invention preferably degrade 2%, 3%, 5%, 10%, 15%, 20%, 30%, 40%, 50%, 75%, 90% or less compared to naturally occurring GCC angonists and/or SP-304.

The GCC agonists for use in the formulations and methods of the invention are preferably peptides. In some embodiments, the GCC agonist peptide is less than 30 amino acids in length. In particular embodiments, the GCC agonist peptide is less than or equal to 30, 25, 20, 15, 14, 13, 12, 11, 10, or 5 amino acids in length. Examples of GCC agonist peptides for use in the formulations and methods of the invention include those described in U.S. Ser. No. 12/133,344, filed Jun. 4, 2008, Ser. No. 12/478,505, filed Jun. 4, 2009; Ser. No. 12/478,511, filed Jun. 4, 2009; Ser. No. 12/504,288, filed Jul. 16, 2009; and U.S. Provisional Application Ser. Nos. 60/933,194, filed Jun. 4, 2007; 61/058,888, filed Jun. 4, 2008; 61/058,892, filed Jun. 4, 2008; and 61/081,289, filed Jul. 16, 2008, each of which is incorporated by reference herein in its entirety.

Specific examples of GCC agonist peptides for use in the formulations and methods of the invention include those described in Tables I-VII below. As used Tables I-VII, the terms “PEG3” or “3PEG” refer to a polyethylene glycol such as aminoethyloxy-ethyloxy-acetic acid (AeeA), and polymers thereof. The term “X_(aa)” refers to any natural or unnatural amino acid or amino acid analogue. The term “M_(aa)” refers to a cysteine (Cys), penicillamine (Pen) homocysteine, or 3-mercaptoproline. The term “Xaa_(n1)” is meant to denote an amino acid sequence of any natural or unnatural amino acid or amino acid analogue that is one, two or three residues in length; Xaa_(n2) is meant to denote an amino acid sequence that is zero or one residue in length; and Xaa_(n3) is meant to denote an amino acid sequence zero, one, two, three, four, five or six residues in length. Additionally, any amino acid represented by Xaa, Xaa_(n1), Xaa_(n2), or Xaa_(n3) may be an L-amino acid, a D-amino acid, a methylated amino acid or any combination of thereof. Optionally, any GCC agonist peptide represented by Formulas I to XX in the tables may contain on or more polyethylene glycol residues at the N-terminus, C-terminus or both.

In certain embodiments, a GCC agonist formulation of the invention comprises a peptide selected from SEQ ID NOs: 1-249, the sequences of which are set forth below in Tables I to VII below. In one embodiment, a GCC agonist formulation comprises the peptide designated by SEQ ID NOs:1, 8, 9, 55, or 56.

In certain embodiments, a GCC agonist formulation of the invention comprises a peptide that is substantially equivalent to a peptide selected from SEQ ID NOs: 1-249. The term “substantially equivalent” refers to a peptide that has an amino acid sequence equivalent to that of the binding domain where certain residues may be deleted or replaced with other amino acids without impairing the peptide's ability to bind to an intestinal guanylate cyclase receptor and stimulate fluid and electrolyte transport.

1.2.1 GCC Agonist Peptides

In a preferred embodiment, the GCC agonists for use in the formulations and methods of the invention are GCC agonist peptides. In certain embodiments, the GCC agonist peptides are analogues of uroguanylin or a bacterial ST peptide. Uroguanylin is a circulating peptide hormone with natriuretic activity. An ST peptide is a member of a family of heat stable enterotoxins (ST peptides) secreted by pathogenic strains of E. coli and other enteric bacteria that activate guanylate cyclase receptor and cause secretory diarrhea. Unlike bacterial ST peptides, the binding of uroguanylin to guanylate cyclase receptor is dependent on the physiological pH of the gut. Therefore, uroguanylin is expected to regulate fluid and electrolyte transport in a pH dependent manner and without causing severe diarrhea.

The GCC agonist peptides for use in the formulations and methods of the invention can be polymers of L-amino acids, D-amino acids, or a combination of both. For example, in various embodiments, the peptides are D retro-inverso peptides. The term “retro-inverso isomer” refers to an isomer of a linear peptide in which the direction of the sequence is reversed and the chirality of each amino acid residue is inverted. See, e.g., Jameson et al., Nature, 368, 744-746 (1994); Brady et al., Nature, 368, 692-693 (1994). The net result of combining D-enantiomers and reverse synthesis is that the positions of carbonyl and amino groups in each amide bond are exchanged, while the position of the side-chain groups at each alpha carbon is preserved. Unless specifically stated otherwise, it is presumed that any given L-amino acid sequence of the invention may be made into an D retro-inverso peptide by synthesizing a reverse of the sequence for the corresponding native L-amino acid sequence.

The GCC agonist peptides for use in the formulations and methods of the invention are able to induce intracellular cGMP production in cells and tissues expressing guanylate cyclase C. In certain embodiments, the GCC agonist peptide stimulates 5%, 10%, 20%, 30%, 40%, 50%, 75%, 90% or more intracellular cGMP compared to naturally occurring GCC agonists such as uroguanylin, guanylin, or ST peptides. Optionally, the GCC agonist peptide stimulates 5%, 10%, 20%, 30%, 40%, 50%, 75%, 90% or more intracellular cGMP compared SP-304 (SEQ ID NO:1). In further embodiments, the GCC agonist peptide stimulates apoptosis, e.g., programmed cell death, or activate the cystic fibrosis transmembrane conductance regulator (CFTR).

In some embodiments, the GCC agonist peptides for use in the formulations and methods of the invention are more stable than naturally occurring GCC agonists and/or SP-304 (SEQ ID NO:1), SP-339 (linaclotide) (SEQ ID NO: 55) or SP-340 (SEQ ID NO: 56). For example, the GCC agonist peptide degrades 2%, 3%, 5%, 10%, 15%, 20%, 30%, 40%, 50%, 75%, 90% or less compared to naturally occurring GCC agonists and/or SP-304, SP-339 (linaclotide) or SP-340. In certain embodiments, the GCC agonist peptides for use in the formulations and methods of the invention are more stable to proteolytic digestion than naturally occurring GCC agonists and/or SP-304 (SEQ ID NO:1), SP-339 (linaclotide) (SEQ ID NO: 55) or SP-340 (SEQ ID NO: 56). In one embodiment, a GCC agonist peptide is pegylated in order to render the peptides more resistant towards proteolysis by enzymes of the gastrointestinal tract. In a preferred embodiment, the GCC agonist peptide is pegylated with the aminoethyloxy-ethyloxy-acetic acid (Aeea) group at its C-terminal end, at its N-terminal end, or at both termini.

Specific examples of GCC agonist peptides that can be used in the methods and formulations of the invention include a peptide selected from the group designated by SEQ ID NOs: 1-249.

In one embodiment, the GCC agonist peptide is a peptide having the amino acid sequence of any one of Formulas X-XVII (e.g. SEQ ID NO:87-98).

In some embodiments, GCC agonist peptides include peptides having the amino acid sequence of Formula I, wherein at least one amino acid of Formula I is a D-amino acid or a methylated amino acid and/or the amino acid at position 16 is a serine. Preferably, the amino acid at position 16 of Formula I is a D-amino acid or a methylated amino acid. For example, the amino acid at position 16 of Formula I is a d-leucine or a d-serine. Optionally, one or more of the amino acids at positions 1-3 of Formula I are D-amino acids or methylated amino acids or a combination of D-amino acids or methylated amino acids. For example, Asn¹, Asp² or Glu³ (or a combination thereof) of Formula I is a D-amino acid or a methylated amino acid. Preferably, the amino acid at position Xaa⁶ of Formula I is a leucine, serine or tyrosine.

In alternative embodiments, GCC agonist peptides include peptides having the amino acid sequence of Formula II, wherein at least one amino acid of Formula II is a D-amino acid or a methylated amino acid. Preferably, the amino acid denoted by Xaa_(n2) of Formula II is a D-amino acid or a methylated amino acid. In some embodiments, the amino acid denoted by Xaa_(n2) of Formula II is a leucine, a d-leucine, a serine, or a d-serine. Preferably, the one or more amino acids denoted by Xaa_(n1) of Formula II is a D-amino acid or a methylated amino acid. Preferably, the amino acid at position Xaa⁶ of Formula II is a leucine, a serine, or a tyrosine.

In some embodiments, GCC agonist peptides include peptides having the amino acid sequence of Formula III, wherein at least one amino acid of Formula III is a D-amino acid or a methylated amino acid and/or Maa is not a cysteine. Preferably, the amino acid denoted by Xaa_(n2) of Formula III is a D-amino acid or a methylated amino acid. In some embodiments the amino acid denoted by Xaa_(n2) of Formula III is a leucine, a d-leucine, a serine, or a d-serine. Preferably, the one or more amino acids denoted by Xaa_(n1) of Formula III is a D-amino acid or a methylated amino acid. Preferably, the amino acid at position Xaa⁶ of Formula III is a leucine, a serine, or a tyrosine.

In other embodiments, GCC agonist peptides include peptides having the amino acid sequence of Formula IV, wherein at least one amino acid of Formula IV is a D-amino acid or a methylated amino acid, and/or Maa is not a cysteine. Preferably, the Xaa_(n2) of Formula IV is a D-amino acid or a methylated amino acid. In some embodiments, the amino acid denoted by Xaa_(n2) of Formula IV is a leucine, a d-leucine, a serine, or a d-serine. Preferably, the one or more of the amino acids denoted by Xaa_(n1) of Formula IV is a D-amino acid or a methylated amino acid. Preferably, the amino acid denoted Xaa⁶ of Formula IV is a leucine, a serine, or a tyrosine.

In further embodiments, GCC agonist peptides include peptides having the amino acid sequence of Formula V, wherein at at least one amino acid of Formula V is a D-amino acid or a methylated amino acid. Preferably, the amino acid at position 16 of Formula V is a D-amino acid or a methylated amino acid. For example, the amino acid at position 16 (i.e., Xaa¹⁶) of Formula V is a d-leucine or a d-serine. Optionally, one or more of the amino acids at position 1-3 of Formula V are D-amino acids or methylated amino acids or a combination of D-amino acids or methylated amino acids. For example, Asn¹, Asp² or Glu³ (or a combination thereof) of Formula V is a D-amino acids or a methylated amino acid. Preferably, the amino acid denoted at Xaa⁶ of Formula V is a leucine, a serine, or a tyrosine.

In additional embodiments, GCC agonist peptides include peptides having the amino acid sequence of Formula VI, VII, VIII, or IX. Preferably, the amino acid at position 6 of Formula VI, VII, VIII, or IX is a leucine, a serine, or a tyrosine. In some aspects the amino acid at position 16 of Formula VI, VII, VIII, or IX is a leucine or a serine. Preferably, the amino acid at position 16 of Formula V is a D-amino acid or a methylated amino acid.

In additional embodiments, GCC agonist peptides include peptides having the amino acid sequence of Formula X, XI, XII, XIII, XIV, XV, XVI or XVII. Optionally, one or more amino acids of Formulas X, XI, XII, XIII, XIV, XV, XVI or XVII is a D-amino acid or a methylated amino acid. Preferably, the amino acid at the carboxy terminus of the peptides according to Formulas X, XI, XII, XIII, XIV, XV, XVI or XVII is a D-amino acid or a methylated amino acid. For example the the amino acid at the carboxy terminus of the peptides according to Formulas X, XI, XII, XIII, XIV, XV, XVI or XVII is a D-tyrosine.

Preferably, the amino acid denoted by Xaa⁶ of Formula XIV is a tyrosine, phenyalanine or a serine. Most preferably the amino acid denoted by Xaa⁶ of Formula XIV is a phenyalanine or a serine. Preferably, the amino acid denoted by Xaa⁴ of Formula XV, XVI or XVII is a tyrosine, a phenyalanine, or a serine. Most preferably, the amino acid position Xaa⁴ of Formula V, XVI or XVII is a phenyalanine or a serine.

In some embodiments, GCRA peptides include peptides containing the amino acid sequence of Formula XVIII. Preferably, the amino acid at position 1 of Formula XVIII is a glutamic acid, aspartic acid, glutamine or lysine. Preferably, the amino acid at position 2 and 3 of Formula XVIII is a glutamic acid, or an aspartic acid. Preferably, the amino acid at position 5 a glutamic acid. Preferably, the amino acid at position 6 of Formula XVIII is an isoleucine, valine, serine, threonine or tyrosine. Preferably, the amino acid at position 8 of Formula XVIII is a valine or isoleucine. Preferably, the amino acid at position 9 of Formula XVIII is a an asparagine. Preferably, the amino acid at position 10 of Formula XVIII is a valine or an methionine. Preferably, the amino acid at position 11 of Formula XVIII is an alanine Preferably, the amino acid at position 13 of Formula XVIII is a threonine. Preferably, the amino acid at position 14 of Formula XVIII is a glycine. Preferably, the amino acid at position 16 of Formula XVIII is a leucine, serine or threonine

In alternative embodiments, GCRA peptides include peptides containing the amino acid sequence of Formula XIX. Preferably, the amino acid at position 1 of Formula XIX is a serine or asparagine. Preferably, the amino acid at position 2 of Formula XIX is a histidine or an aspartic acid. Preferably, the amino acid at position 3 of Formula XIX is a threonine or a glutamic acid. Preferably, the amino acid at position 5 of Formula XIX is a glutamic acid. Preferably, the amino acid at position 6 of Formula XIX is an isoleucine, leucine, valine or tyrosine. Preferably, the amino acid at position 8, 10, 11, or 13 of Formula XIX is a alanine Preferably, the amino acid at position 9 of Formula XIX is an asparagine or a phenylalanine Preferably, the amino acid at position 14 of Formula XIX is a glycine.

In further embodiments, GCRA peptides include peptides containing the amino acid sequence of Formula XX. Preferably, the amino acid at position 1 of Formula XX is a glutamine. Preferably, the amino acid at position 2 or 3 of Formula XX is a glutamic acid or a aspartic acid. Preferably, the amino acid at position 5 of Formula XX is a glutamic acid. Preferably, the amino acid at position 6 of Formula XX is threonine, glutamine, tyrosine, isoleucine, or leucine. Preferably, the amino acid at position 8 of Formula XX is isoleucine or valine. Preferably, the amino acid at position 9 of Formula XX is asparagine. Preferably, the amino acid at position 10 of Formula XX is methionine or valine. Preferably, the amino acid at position 11 of Formula XX is alanine Preferably, the amino acid at position 13 of Formula XX is a threonione. Preferably, the amino acid at position 1 of Formula XX is a glycine. Preferably, the amino acid at position 15 of Formula XX is a tyrosine. Optionally, the amino acid at position 15 of Formula XX is two amino acid in length and is Cysteine (Cys), Penicillamine (Pen) homocysteine, or 3-mercaptoproline and serine, leucine or threonine.

In certain embodiments, one or more amino acids of the GCC agonist peptides are replaced by a non-naturally occurring amino acid or a naturally or non-naturally occurring amino acid analog. Such amino acids and amino acid analogs are known in the art. See, for example, Hunt, “The Non-Protein Amino Acids,” in Chemistry and Biochemistry of the Amino Acids, Barrett, Chapman and Hall, 1985. In some embodiments, an amino acid is replaced by a naturally-occurring, non-essential amino acid, e.g., taurine. Non-limiting examples of naturally occurring amino acids that can be replaced by non-protein amino acids include the following: (1) an aromatic amino acid can be replaced by 3,4-dihydroxy-L-phenylalanine, 3-iodo-L-tyrosine, triiodothyronine, L-thyroxine, phenylglycine (Phg) or nor-tyrosine (norTyr); (2) Phg and norTyr and other amino acids including Phe and Tyr can be substituted by, e.g., a halogen, —CH3, —OH, —CH2NH3, —C(O)H, —CH2CH3, —CN, —CH2CH2CH3, —SH, or another group; (3) glutamine residues can be substituted with gamma-Hydroxy-Glu or gamma-Carboxy-Glu; (4) tyrosine residues can be substituted with an alpha substituted amino acid such as L-alpha-methylphenylalanine or by analogues such as: 3-Amino-Tyr; Tyr(CH3); Tyr(PO3(CH3)2); Tyr(SO3H); beta-Cyclohexyl-Ala; beta-(1-Cyclopentenyl)-Ala; beta-Cyclopentyl-Ala; beta-Cyclopropyl-Ala; beta-Quinolyl-Ala; beta-(2-Thiazolyl)-Ala; beta-(Triazole-1-yl)-Ala; beta-(2-Pyridyl)-Ala; beta-(3-Pyridyl)-Ala; Amino-Phe; Fluoro-Phe; Cyclohexyl-Gly; tBu-Gly; beta-(3-benzothienyl)-Ala; beta-(2-thienyl)-Ala; 5-Methyl-Tip; and A-Methyl-Trp; (5) proline residues can be substituted with homopro (L-pipecolic acid); hydroxy-Pro; 3,4-Dehydro-Pro; 4-fluoro-Pro; or alpha-methyl-Pro or an N(alpha)-C(alpha) cyclized amino acid analogues with the structure: n=0, 1, 2, 3; and (6) alanine residues can be substituted with alpha-substituted or N-methylated amino acid such as alpha-amino isobutyric acid (aib), L/D-alpha-ethylalanine (L/D-isovaline), L/D-methylvaline, or L/D-alpha-methylleucine or a non-natural amino acid such as beta-fluoro-Ala. Alanine can also be substituted with: n=0, 1, 2, 3 Glycine residues can be substituted with alpha-amino isobutyric acid (aib) or L/D-alpha-ethylalanine (L/D-isovaline).

Further examples of non-natural amino acids include: an unnatural analog of tyrosine; an unnatural analogue of glutamine; an unnatural analogue of phenylalanine; an unnatural analogue of serine; an unnatural analogue of threonine; an alkyl, aryl, acyl, azido, cyano, halo, hydrazine, hydrazide, hydroxyl, alkenyl, alkynl, ether, thiol, sulfonyl, seleno, ester, thioacid, borate, boronate, phospho, phosphono, phosphine, heterocyclic, enone, imine, aldehyde, hydroxylamine, keto, or amino substituted amino acid, or any combination thereof; an amino acid with a photoactivatable cross-linker; a spin-labeled amino acid; a fluorescent amino acid; an amino acid with a novel functional group; an amino acid that covalently or noncovalently interacts with another molecule; a metal binding amino acid; an amino acid that is amidated at a site that is not naturally amidated, a metal-containing amino acid; a radioactive amino acid; a photocaged and/or photoisomerizable amino acid; a biotin or biotin-analogue containing amino acid; a glycosylated or carbohydrate modified amino acid; a keto containing amino acid; amino acids comprising polyethylene glycol or polyether; a heavy atom substituted amino acid (e.g., an amino acid containing deuterium, tritium, ¹³C, ¹⁵N, or ¹⁸O); a chemically cleavable or photocleavable amino acid; an amino acid with an elongated side chain; an amino acid containing a toxic group; a sugar substituted amino acid, e.g., a sugar substituted serine or the like; a carbon-linked sugar-containing amino acid; a redox-active amino acid; an α-hydroxy containing acid; an amino thio acid containing amino acid; an α, α disubstituted amino acid; a β-amino acid; a cyclic amino acid other than proline; an O-methyl-L-tyrosine; an L-3-(2-naphthyl)alanine; a 3-methyl-phenylalanine; a ρ-acetyl-L-phenylalanine; an O-4-allyl-L-tyrosine; a 4-propyl-L-tyrosine; a tri-O-acetyl-GlcNAc β-serine; an L-Dopa; a fluorinated phenylalanine; an isopropyl-L-phenylalanine; a p-azido-L-phenylalanine; a p-acyl-L-phenylalanine; a p-benzoyl-L-phenylalanine; an L-phosphoserine; a phosphonoserine; a phosphonotyrosine; a p-iodo-phenylalanine; a 4-fluorophenylglycine; a p-bromophenylalanine; a p-amino-L-phenylalanine; an isopropyl-L-phenylalanine; L-3-(2-naphthyl)alanine; D-3-(2-naphthyl)alanine (dNal); an amino-, isopropyl-, or O-allyl-containing phenylalanine analogue; a dopa, 0-methyl-L-tyrosine; a glycosylated amino acid; a p-(propargyloxy)phenylalanine; dimethyl-Lysine; hydroxy-proline; mercaptopropionic acid; methyl-lysine; 3-nitro-tyrosine; norleucine; pyro-glutamic acid; Z (Carbobenzoxyl); ε-Acetyl-Lysine; β-alanine; aminobenzoyl derivative; aminobutyric acid (Abu); citrulline; aminohexanoic acid; aminoisobutyric acid (AIB); cyclohexylalanine; d-cyclohexylalanine; hydroxyproline; nitro-arginine; nitro-phenylalanine; nitro-tyrosine; norvaline; octahydroindole carboxylate; ornithine (Om); penicillamine (PEN); tetrahydroisoquinoline; acetamidomethyl protected amino acids and pegylated amino acids. Further examples of unnatural amino acids and amino acid analogs can be found in U.S. 20030108885, U.S. 20030082575, US20060019347 (paragraphs 410-418) and the references cited therein. The polypeptides of the invention can include further modifications including those described in 0520060019347, paragraph 589. Exemplary GCC agonist peptides which include a non-naturally occurring amino acid include for example SP-368 and SP-369.

In some embodiments, the GCC agonist peptides are cyclic peptides. GCC agonist cyclic peptides can be prepared by methods known in the art. For example, macrocyclization is often accomplished by forming an amide bond between the peptide N- and C-termini, between a side chain and the N- or C-terminus [e.g., with K₃Fe(CN)₆ at pH 8.5] (Samson et al., Endocrinology, 137: 5182-5185 (1996)), or between two amino acid side chains, such as cysteine. See, e.g., DeGrado, Adv Protein Chem, 39: 51-124 (1988). In various embodiments, the GCC agonist peptides are [4,12; 7,15] bicycles.

In certain embodiments, one or both Cys residues which normally form a disulfide bond in a GCC agonist peptide are replaced with homocysteine, penicillamine, 3-mercaptoproline (Kolodziej et al. 1996 Int. J. Pept. Protein Res. 48:274), β, β dimethylcysteine (Hunt et al. 1993 Int. J. Pept. Protein Res. 42:249), or diaminopropionic acid (Smith et al. 1978 J. Med. Chem. 2 1:117) to form alternative internal cross-links at the positions of the normal disulfide bonds.

In certain embodiments, one or more disulfide bonds in a GCC agonist peptide are replaced by alternative covalent cross-links, e.g., an amide linkage (—CH₂CH(O)NHCH₂— or —CH₂NHCH(O)CH₂—), an ester linkage, a thioester linkage, a lactam bridge, a carbamoyl linkage, a urea linkage, a thiourea linkage, a phosphonate ester linkage, an alkyl linkage (—CH₂CH₂CH₂CH₂—), an alkenyl linkage (—CH₂CH═CHCH₂—), an ether linkage (—CH₂CH₂OCH₂— or —CH₂OCH₂CH₂—), a thioether linkage (—CH₂CH₂SCH₂— or —CH₂SCH₂CH₂—), an amine linkage (—CH₂CH₂NHCH₂— or —CH₂NHCH₂CH₂—) or a thioamide linkage (—CH₂CH(S)HNHCH₂— or —CH₂NHCH(S)CH₂—). For example, Ledu et al. (Proc. Natl. Acad. Sci. 100:11263-78, 2003) describe methods for preparing lactam and amide cross-links. Exemplary GCC agonist peptides which include a lactam bridge include, for example, SP-370.

In certain embodiments, the GCC agonist peptides have one or more conventional polypeptide bonds replaced by an alternative bond. Such replacements can increase the stability of the polypeptide. For example, replacement of the polypeptide bond between a residue amino terminal to an aromatic residue (e.g. Tyr, Phe, Trp) with an alternative bond can reduce cleavage by carboxy peptidases and may increase half-life in the digestive tract. Bonds that can replace polypeptide bonds include: a retro-inverso bond (C(O)—NH instead of NH—C(O); a reduced amide bond (NH—CH₂); a thiomethylene bond (S—CH₂ or CH₂—S); an oxomethylene bond (O—CH₂ or CH₂—O); an ethylene bond (CH₂—CH₂); a thioamide bond (C(S)—NH); a trans-olefine bond (CH═CH); a fluoro substituted trans-olefme bond (CF═CH); a ketomethylene bond (C(O)—CHR or CHR—C(O) wherein R is H or CH₃; and a fluoro-ketomethylene bond (C(O)—CFR or CFR—C(O) wherein R is H or F or CH₃.

In certain embodiments, the GCC agonist peptides are modified using standard modifications. Modifications may occur at the amino (N—), carboxy (C—) terminus, internally or a combination of any of the preceeding. In one aspect described herein, there may be more than one type of modification on the polypeptide. Modifications include but are not limited to: acetylation, amidation, biotinylation, cinnamoylation, farnesylation, formylation, myristoylation, palmitoylation, phosphorylation (Ser, Tyr or Thr), stearoylation, succinylation, sulfurylation and cyclisation (via disulfide bridges or amide cyclisation), and modification by Cys3 or Cys5. The GCC agonist peptides described herein may also be modified by 2,4-dinitrophenyl (DNP), DNP-lysine, modification by 7-Amino-4-methyl-coumarin (AMC), flourescein, NBD (7-Nitrobenz-2-Oxa-1,3-Diazole), p-nitro-anilide, rhodamine B, EDANS (5-((2-aminoethyl)amino)naphthalene-1-sulfonic acid), dabcyl, dabsyl, dansyl, texas red, FMOC, and Tamra (Tetramethylrhodamine). The GCC agonist peptides described herein may also be conjugated to, for example, polyethylene glycol (PEG); alkyl groups (e.g., C1-C20 straight or branched alkyl groups); fatty acid radicals; combinations of PEG, alkyl groups and fatty acid radicals (See, U.S. Pat. No. 6,309,633; Soltero et al., 2001 Innovations in Pharmaceutical Technology 106-110); BSA and KLH (Keyhole Limpet Hemocyanin) The addition of PEG and other polymers which can be used to modify polypeptides of the invention is described in US20060 19347 section IX.

A GCC agonist peptide can also be a derivatives of a GCC agonist peptide described herein. For example, a derivative includes hybrid and modified forms of GCC agonist peptides in which certain amino acids have been deleted or replaced. A modification may also include glycosylation. Preferrably, where the modification is an amino acid substitution, it is a conservative substitution at one or more positions that are predicted to be non-essential amino acid residues for the biological activity of the peptide. A “conservative substitution” is one in which the amino acid residue is replaced with an amino acid residue having a similar side chain. Families of amino acid residues having similar side chains have been defined in the art. These families include amino acids with basic side chains (e.g., lysine, arginine, histidine), acidic side chains (e.g., aspartic acid, glutamic acid), uncharged polar side chains (e.g., glycine, asparagine, glutamine, serine, threonine, tyrosine, cysteine), nonpolar side chains (e.g., alanine, valine, leucine, isoleucine, proline, phenylalanine, methionine, tryptophan), beta-branched side chains (e.g., threonine, valine, isoleucine) and aromatic side chains (e.g., tyrosine, phenylalanine, tryptophan, histidine).

In one embodiment, a GCC agonist peptide described herein is subjected to random mutagenesis in order to identify mutants having biological activity.

In one embodiment, the GCC agonist peptide is substantially homologous is a GCC agonist peptide described herein. Such substantially homologous peptides can be isolated by virtue of cross-reactivity with antibodies to a GCC agonist peptide described herein.

Further examples of GCC agonist peptides that can be used in the methods and formulations of the invention are found in Tables I-VII below.

1.2.2 Preparation of GCC Agonist Peptides

GCC agonist peptides can be prepared using art recognized techniques such as molecular cloning, peptide synthesis, or site-directed mutagenesis.

Peptide synthesis can be performed using standard solution phase or solid phase peptide synthesis techniques in which a peptide linkage occurs through the direct condensation of the amino group of one amino acid with the carboxy group of the other amino acid with the elimination of a water molecule. Peptide bond synthesis by direct condensation, as formulated above, requires suppression of the reactive character of the amino group of the first and of the carboxyl group of the second amino acid. The masking substituents must permit their ready removal, without inducing breakdown of the labile peptide molecule.

In solution phase synthesis, a wide variety of coupling methods and protecting groups may be used (See, Gross and Meienhofer, eds., “The Peptides: Analysis, Synthesis, Biology,” Vol. 1-4 (Academic Press, 1979); Bodansky and Bodansky, “The Practice of Peptide Synthesis,” 2d ed. (Springer Verlag, 1994)). In addition, intermediate purification and linear scale up are possible. Those of ordinary skill in the art will appreciate that solution synthesis requires consideration of main chain and side chain protecting groups and activation method. In addition, careful segment selection is necessary to minimize racemization during segment condensation. Solubility considerations are also a factor. Solid phase peptide synthesis uses an insoluble polymer for support during organic synthesis. The polymer-supported peptide chain permits the use of simple washing and filtration steps instead of laborious purifications at intermediate steps. Solid-phase peptide synthesis may generally be performed according to the method of Merrifield et al., J. Am. Chem. Soc., 1963, 85:2149, which involves assembling a linear peptide chain on a resin support using protected amino acids. Solid phase peptide synthesis typically utilizes either the Boc or Fmoc strategy, which are well known in the art.

Those of ordinary skill in the art will recognize that, in solid phase synthesis, deprotection and coupling reactions must go to completion and the side-chain blocking groups must be stable throughout the synthesis. In addition, solid phase synthesis is generally most suitable when peptides are to be made on a small scale.

Acetylation of the N-terminal can be accomplished by reacting the final peptide with acetic anhydride before cleavage from the resin. C-amidation is accomplished using an appropriate resin such as methylbenzhydrylamine resin using the Boc technology.

Alternatively the GCC agonist peptides are produced by modern cloning techniques For example, the GCC agonist peptides are produced either in bacteria including, without limitation, E. coli, or in other existing systems for polypeptide or protein production (e.g., Bacillus subtilis, baculovirus expression systems using Drosophila Sf9 cells, yeast or filamentous fungal expression systems, mammalian cell expression systems), or they can be chemically synthesized. If the GCC agonist peptide or variant peptide is to be produced in bacteria, e.g., E. coli, the nucleic acid molecule encoding the polypeptide may also encode a leader sequence that permits the secretion of the mature polypeptide from the cell. Thus, the sequence encoding the polypeptide can include the pre sequence and the pro sequence of, for example, a naturally-occurring bacterial ST polypeptide. The secreted, mature polypeptide can be purified from the culture medium.

The sequence encoding a GCC agonist peptide described herein can be inserted into a vector capable of delivering and maintaining the nucleic acid molecule in a bacterial cell. The DNA molecule may be inserted into an autonomously replicating vector (suitable vectors include, for example, pGEM3Z and pcDNA3, and derivatives thereof). The vector nucleic acid may be a bacterial or bacteriophage DNA such as bacteriophage lambda or M13 and derivatives thereof. Construction of a vector containing a nucleic acid described herein can be followed by transformation of a host cell such as a bacterium. Suitable bacterial hosts include but are not limited to, E. coli, B subtilis, Pseudomonas, Salmonella. The genetic construct also includes, in addition to the encoding nucleic acid molecule, elements that allow expression, such as a promoter and regulatory sequences. The expression vectors may contain transcriptional control sequences that control transcriptional initiation, such as promoter, enhancer, operator, and repressor sequences.

A variety of transcriptional control sequences are well known to those in the art. The expression vector can also include a translation regulatory sequence (e.g., an untranslated 5′ sequence, an untranslated 3′ sequence, or an internal ribosome entry site). The vector can be capable of autonomous replication or it can integrate into host DNA to ensure stability during polypeptide production.

The protein coding sequence that includes a GCC agonist peptide described herein can also be fused to a nucleic acid encoding a polypeptide affinity tag, e.g., glutathione S-transferase (GST), maltose E binding protein, protein A, FLAG tag, hexa-histidine, myc tag or the influenza HA tag, in order to facilitate purification. The affinity tag or reporter fusion joins the reading frame of the polypeptide of interest to the reading frame of the gene encoding the affinity tag such that a translational fusion is generated. Expression of the fusion gene results in translation of a single polypeptide that includes both the polypeptide of interest and the affinity tag. In some instances where affinity tags are utilized, DNA sequence encoding a protease recognition site will be fused between the reading frames for the affinity tag and the polypeptide of interest.

Genetic constructs and methods suitable for production of immature and mature forms of the GCC agonist peptides and variants described herein in protein expression systems other than bacteria, and well known to those skilled in the art, can also be used to produce polypeptides in a biological system.

The peptides disclosed herein may be modified by attachment of a second molecule that confers a desired property upon the peptide, such as increased half-life in the body, for example, pegylation. Such modifications also fall within the scope of the term “variant” as used herein.

TABLE I GCRA Peptides (SP-304 and Derivatives) Position SEQ of Disulfide ID Name bonds Structure NO SP-304 C4:C12, C7:C15 Asn¹-Asp²-Glu³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Val⁸-Asn⁹-Val¹⁰-Ala¹¹-Cys¹²-Thr¹³-Gly¹⁴-  1 Cys¹⁵-Leu¹⁶ SP-326 C3:C11, C6:C14 Asp¹-Glu²-Cys³-Glu⁴-Leu⁵-Cys⁶-Val⁷-Asn⁸-Val⁹-Ala¹⁰-Cys¹¹-Thr¹²-Gly¹³-Cys¹⁴-  2 Leu¹⁵ SP-327 C2:C10, C5:C13 Asp¹-Glu²-Cys³-Glu⁴-Leu⁵-Cys⁶-Val⁷-Asn⁸-Val⁹-Ala¹⁰-Cys¹¹-Thr¹²-Gly¹³-Cys¹⁴  3 SP-328 C2:C10, C5:C13 Glu¹-Cys²-Glu³-Leu⁴-Cys⁵-Val⁶-Asn⁷-Val⁸-Ala⁹-Cys¹⁰-Thr¹¹-Gly¹²-Cys¹³-Leu¹⁴  4 SP-329 C2:C10, C5:C13 Glu¹-Cys²-Glu³-Leu⁴-Cys⁵-Val⁶-Asn⁷-Val⁸-Ala⁹-Cys¹⁰-Thr¹¹-Gly¹²-Cys¹³  5 SP-330 C1:C9, C4:C12 Cys¹-Glu²-Leu³-Cys⁴-Val⁵-Asn⁶-Val⁷-Ala⁸-Cys⁹-Thr¹⁰-Gly¹¹-Cys¹²-Leu¹³  6 SP-331 C1:C9, C4:C12 Cys¹-Glu²-Leu³-Cys⁴-Val⁵-Asn⁶-Val⁷-Ala⁸-Cys⁹-Thr¹⁰-Gly¹¹-Cys¹²  7 SP332 C4:C12, C7:C15 Asn¹-Asp²-Glu³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Val⁸-Asn⁹-Val¹⁰-Ala¹¹-Cys¹²-Thr¹³-Gly¹⁴-  8 Cys¹⁵-dLeu¹⁶ SP-333 C4:C12, C7:C15 dAsn¹-Asp²-Glu³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Val⁸-Asn⁹-Val¹⁰-Ala¹¹-Cys¹²-Thr¹³-Gly¹⁴-  9 Cys¹⁵-dLeu¹⁶ SP-334 C4:C12, C7:C15 dAsn¹-dAsp²-Glu³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Val⁸-Asn⁹-Val¹⁰-Ala¹¹-Cys¹²-Thr¹³-Gly¹⁴- 10 Cys¹⁵-dLeu¹⁶ SP-335 C4:C12, C7:C15 dAsn¹-dAsp²-dGlu³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Val⁸-Asn⁹-Val¹⁰-Ala¹¹-Cys¹²-Thr¹³-Gly¹⁴- 11 Cys¹⁵-dLeu¹⁶ SP-336 C4:C12, C7:C15 dAsn¹-Asp²-Glu³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Val⁸-Asn⁹-Val¹⁰-Ala¹¹-Cys¹²-Thr¹³-Gly¹⁴- 12 Cys¹⁵-Leu¹⁶ SP-337 C4:C12, C7:C15 dAsn¹-Asp²-Glu³-Cys⁴-Glu⁵-dLeu⁶-Cys⁷-Val⁸-Asn⁹-Val¹⁰-Ala¹¹-Cys¹²-Thr¹³-Gly¹⁴- 13 Cys¹⁵-dLeu¹⁶ SP-338 C4:C12, C7:C15 Asn¹-Asp²-Glu³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Val⁸-Asn⁹-Val¹⁰-Ala¹¹-Cys¹²-Thr¹³-Gly¹⁴- 14 Cys¹⁵ SP-342 C4:C12, C7:C15 PEG3-Asn¹-Asp²-Glu³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Val⁸-Asn⁹-Val¹⁰-Ala¹¹-Cys¹²-Thr¹³- 15 Gly¹⁴-Cys¹⁵-dLeu¹⁶-PEG3 SP-343 C4:C12, C7:C15 PEG3-dAsn¹-Asp²-Glu³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Val⁸-Asn⁹-Val¹⁰-Ala¹¹-Cys¹²-Thr¹³- 16 Gly¹⁴-Cys¹⁵-dLeu¹⁶-PEG3 SP-344 C4:C12, C7:C15 PEG3-dAsn¹-dAsp²-Glu³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Val⁸-Asn⁹-Val¹⁰-Ala¹¹-Cys¹²-Thr¹³- 17 Gly¹⁴⁻Cys¹⁵⁻dLeu¹⁶-PEG3 SP-347 C4:C12, C7:C15 dAsn¹-Asp²-Glu³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Val⁸-Asn⁹-Val¹⁰-Ala¹¹-Cys¹²-Thr¹³-Gly¹⁴- 18 Cys¹⁵-dLeu¹⁶-PEG3 SP-348 C4:C12, C7:C15 PEG3-Asn¹-Asp²-Glu³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Val⁸-Asn⁹-Val¹⁰-Ala¹¹-Cys¹²-Thr¹³- 19 Gly¹⁴-Cys¹⁵-dLeu¹⁶ SP-350 C4:C12, C7:C15 PEG3-dAsn¹-Asp²-Glu³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Val⁸-Asn⁹-Val¹⁰-Ala¹¹-Cys¹²-Thr¹³- 20 Gly¹⁴-Cys¹⁵-dLeu¹⁶ SP-352 C4:C12, C7:C15 Asn1-Asp²-Glu³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Val⁸-Asn⁹-Val¹⁰-Ala¹¹-Cys¹²-Thr¹³-Gly¹⁴- 21 Cys¹⁵-dLeu¹⁶-PEG3 SP-358 C4:C12, C7:C15 PEG3-dAsn¹-dAsp²-dGlu³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Val⁸-Asn⁹-Val¹⁰-Ala¹¹-Cys¹²-Thr¹³- 22 Gly14-Cys¹⁵-dLeu¹⁶-PEG3 SP-359 C4:C12, C7:C15 PEG3-dAsn¹-dAsp²-dGlu³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Val⁸-Asn⁹-Val¹⁰-Ala¹¹-Cys¹²-Thr¹³- 23 Gly¹⁴-Cys¹⁵-dLeu¹⁶ SP-360 C4:C12, C7:C15 dAsn¹-dAsp²-dGlu³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Val⁸-Asn⁹-Val¹⁰-Ala¹¹-Cys¹²-Thr¹³-Gly¹⁴- 24 Cys¹⁵-dLeu¹⁶⁻PEG3 SP-361 C4:C12, C7:C15 dAsn¹-dAsp²-Glu³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Val⁸-Asn⁹-Val¹⁰-Ala¹¹-Cys¹²-Thr¹³-Gly¹⁴- 25 Cys¹⁵-dLeu¹⁶-PEG3 SP-362 C4:C12, C7:C15 PEG3-dAsn¹-dAsp²-Glu³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Val⁸-Asn⁹-Val¹⁰-Ala¹¹-Cys¹²-Thr¹³- 26 Gly¹⁴-Cys¹⁵-dLeu¹⁶ SP-368 C4:C12, C7:C15 dAsn¹-Asp²-Glu³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Val⁸-Asn⁹-Val¹⁰-Ala¹¹-Cys¹²-Thr¹³-Gly¹⁴- 27 Cys¹⁵-dNal¹⁶ SP-369 C4:C12, C7:C15 dAsn¹-Asp²-Glu³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-AIB⁸-Asn⁹-AIB¹⁰-Ala¹¹-Cys¹²-Thr¹³-Gly¹⁴- 28 Cys¹⁵-dLeu¹⁶ SP-370 C4:C12, C7:C15 dAsn¹-Asp²-Glu³-Cys⁴-Glu⁵-Leu⁶-Asp[Lactam]⁷-Val⁸-Asn⁹-Val¹⁰-Ala¹¹-Cys¹²-Thr¹³- 29 Gly¹⁴-Orn¹⁵-dLeu¹ SP-371 C4:C12, C7:C15 dAsn¹-Asp²-Glu³-Cys⁴-Glu⁵-Tyr⁶-Cys⁷-Val⁸-Asn⁹-Val¹⁰-Ala¹¹-Cys¹²-Thr¹³-Gly¹⁴- 30 Cys¹⁵-dLeu¹⁶ SP-372 C4:C12, C7:C15 dAsn¹-Asp²-Glu³-Cys⁴-Glu⁵-Ser⁶-Cys⁷-Val⁸-Asn⁹-Val¹⁰-Ala¹¹-Cys¹²-Thr¹³-Gly¹⁴- 31 Cys¹⁵-dLeu¹⁶ N1 C4:C12, C7:C15 PEG3-dAsn¹-Asp²-Glu³-Cys⁴-Glu⁵-Tyr⁶-Cys⁷-Val⁸-Asn⁹-Val¹⁰-Ala¹¹-Cys¹²-Thr¹³- 32 Gly¹⁴-Cys¹⁵-dLeu¹⁶-PEG3 N2 C4:C12, C7:C15 PEG3-dAsn¹-Asp²-Glu³-Cys⁴-Glu⁵-Tyr⁶-Cys⁷-Val⁸-Asn⁹-Val¹⁰-Ala¹¹-Cys¹²-Thr¹³- 33 Gly¹⁴-Cys¹⁵-dLeu¹⁶ N3 C4:C12, C7:C15 dAsn1-Asp²-Glu³-Cys⁴-Glu⁵-Tyr⁶-Cys⁷-Val⁸-Asn⁹-Val¹⁰-Ala¹¹-Cys¹²-Thr¹³-Gly¹⁴- 34 Cys¹⁵-dLeu¹⁶ PEG3 N4 C4:C12, C7:C15 PEG3-dAsn¹-Asp²-Glu³-Cys⁴-Glu⁵-Ser⁶-Cys⁷-Val⁸-Asn⁹-Val¹⁰-Ala¹¹-Cys¹²-Thr¹³- 35 Gly¹⁴-Cys¹⁵-dLeu¹⁶-PEG3 N5 C4:C12, C7:C15 PEG3-dAsn¹-Asp²-Glu³-Cys⁴-Glu⁵-Ser⁶-Cys⁷-Val⁸-Asn⁹-Val¹⁰-Ala¹¹-Cys¹²-Thr¹³- 36 Gly¹⁴-Cys¹⁵-dLeu¹⁶ N6 C4:C12, C7:C15 dAsn¹-Asp²-Glu³-Cys⁴-Glu⁵-Ser⁶-Cys⁷-Val⁸-Asn⁹-Val¹⁰-Ala¹¹-Cys¹²-Thr¹³-Gly¹⁴- 37 Cys¹⁵-dLeu¹⁶-PEG3 N7 C4:C12, C7:C15 Asn¹-Asp²-Glu³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Val⁸-Asn⁹-Val¹⁰-Ala¹¹-Cys¹²-Thr¹³-Gly¹⁴- 38 Cys¹⁵-Ser¹⁶ N8 C4:C12, C7:C15 PEG3-Asn¹-Asp²-Glu³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Val⁸-Asn⁹-Val¹⁰-Ala¹¹-Cys¹²-Thr¹³- 39 Gly¹⁴-Cys¹⁵-Ser¹⁶-PEG3 N9 C4:C12, C7:C15 PEG3-Asn¹-Asp²-Glu³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Val⁸-Asn⁹-Val¹⁰-Ala¹¹-Cys¹²-Thr¹³- 40 Gly¹⁴-Cys¹⁵-Ser¹⁶ N10 C4:C12, C7:C15 Asn¹-Asp²-Glu³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Val⁸-Asn⁹-Val¹⁰-Ala¹¹-Cys¹²-Thr¹³-Gly¹⁴- 41 Cys¹⁵-Ser¹⁶-PEG3 N11 C4:C12, C7:C15 PEG3-Asn¹-Asp²-Glu³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Val⁸-Asn⁹-Val¹⁰-Ala¹¹-Cys¹²-Thr¹³- 42 Gly¹⁴-Cys¹⁵-dSer¹⁶-PEG3 N12 C4:C12, C7:C15 PEG3-Asn¹-Asp²-Glu³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Val⁸-Asn⁹-Val¹⁰-Ala¹¹-Cys¹²-Thr¹³- 43 Gly¹⁴-Cys¹⁵-dSer¹⁶ N13 C4:C12, C7:C15 Asn¹-Asp²-Glu³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Val⁸-Asn⁹-Val¹⁰-Ala¹¹-Cys¹²-Thr¹³-Gly¹⁴- 44 Cys¹⁵-dSer¹⁶-PEG3 Formula C4:C12, C7:C15 Asn¹-Asp²-Glu³-Cys⁴-Xaa⁵-Xaa⁶-Cys⁷-Xaa⁸-Xaa⁹-Xaa¹⁰-Xaa¹¹-Cys¹²-Xaa¹³-Xaa¹⁴- 45 I Cys¹⁵-Xaa¹⁶ Formula C4:C12, C7:C15 Xaa_(n1)-Cys⁴-Xaa⁵-Xaa⁶-Cys⁷-Xaa⁸-Xaa⁹-Xaa¹⁰-Xaa¹¹-Cys¹²-Xaa¹³-Xaa¹⁴-Cys¹⁵- 46 II Xaa_(n2) ¹⁶ Formula 4:12, 7:15 Xaa_(n1)-Maa⁴-Glu⁵-Xaa⁶-Maa⁷-Val⁸-Asn⁹-Val¹⁰-Ala¹¹-Maa¹²-Thr¹³-Gly¹⁴-Maa¹⁵-Xaa_(n2) 47 III Formula 4:12, 7:15 Xaa_(n1)-Maa⁴-Xaa⁵-Xaa⁶-Maa⁷-Xaa⁸-Xaa⁹-Xaa¹⁰-Xaa¹¹-Maa¹²-Xaa¹³-Xaa¹⁴-Maa¹⁵-Xaa_(n2) 48 IV Formula C4:C12, C7:C15 Asn¹-Asp²-Asp³-Cys⁴-Xaa⁵-Xaa⁶-Cys⁷-Xaa⁸-Asn⁹-Xaa¹⁰-Xaa¹¹-Cys¹²-Xaa¹³-Xaa¹⁴- 49 V Cys¹⁵-Xaa¹⁶ Formula C4:C12, C7:C15 dAsn¹-Glu²-Glu³-Cys⁴-Xaa⁵-Xaa⁶-Cys⁷-X3⁸-Asn⁹-Xaa¹⁰-Xaa¹¹-Cys¹²-Xaa¹³-Xaa¹⁴- 50 VI Cys¹⁵-d-Xaa¹⁶ Formula C4:C12, C7:C15 dAsn¹-dGlu²-Asp³-Cys⁴-Xaa⁵-Xaa⁶-Cys⁷-Xaa⁸-Asn⁹-Xaa¹⁰-Xaa¹¹-Cys¹²-Xaa¹³-Xaa¹⁴- 51 VII Cys¹⁵-d-Xaa¹⁶ Formula C4:C12, C7:C15 dAsn¹-dAsp²-Glu³-Cys⁴-Xaa⁵-Xaa⁶-Cys⁷-Xaa⁸-Asn⁹-Xaa¹⁰-Xaa¹¹-Cys¹²-Xaa¹³-Xaa¹⁴- 52 VII Cys¹⁵-d-Xaa¹⁶ Formula C4:C12, C7:C15 dAsn¹-dAsp²-dGlu³-Cys⁴-Xaa⁵-Xaa⁶-Cys⁷-Xaa⁸-Tyr⁹-Xaa¹⁰-Xaa¹¹-Cys¹²-Xaa¹³-Xaa¹⁴- 53 VIII Cys¹⁵-d-Xaa¹⁶ Formula C4:C12, C7:C15 dAsn¹-dGlu²-dGlu³-Cys⁴-Xaa⁵-Xaa⁶-Cys⁷-Xaa⁸-Tyr⁹-Xaa¹⁰-Xaa¹¹-Cys¹²-Xaa¹³-Xaa¹⁴- 54 IX Cys¹⁵-d-Xaa¹⁶

TABLE II Linaclotide and Derivatives Position of SEQ ID Name Disulfide bonds Structure NO: SP-339 C1:C6, C2:C10, Cys¹-Cys²-Glu³-Tyr⁴-Cys⁵-Cys⁶-Asn⁷-Pro⁸-Ala⁹-Cys¹⁰-Thr¹¹-Gly¹²- 55 (linaclotide) C5:13 Cys¹³-Tyr¹⁴ SP-340 C1:C6, C2:C10, Cys¹-Cys²-Glu³-Tyr⁴-Cys⁵-Cys⁶-Asn⁷-Pro⁸-Ala⁹-Cys¹⁰-Thr¹¹-Gly¹²- 56 C5:13 Cys¹³ SP-349 C1:C6, C2:C10, PEG3-Cys¹-Cys²-Glu³-Tyr⁴-Cys⁵-Cys⁶-Asn⁷-Pro⁸-Ala⁹-Cys¹⁰-Thr¹¹- 57 C5:13 Gly¹²-Cys¹³-Tyr¹⁴-PEG3 SP-353 C3:C8, C4:C12, Asn¹-Phe²-Cys³-Cys⁴-Glu⁵-Ser⁶-Cys⁷-Cys⁸-Asn⁹-Pro¹⁰-Ala¹¹-Cys¹²- 58 C7:15 Thr¹³-Gly¹⁴-Cys¹⁵-Tyr¹⁶ SP-354 C3:C8, C4:C12, Asn¹-Phe²-Cys³-Cys⁴-Glu⁵-Phe⁶-Cys⁷-Cys⁸-Asn⁹-Pro¹⁰-Ala¹¹-Cys¹²- 59 C7:15 Thr¹³-Gly¹⁴-Cys¹⁵-Tyr¹⁶ SP-355 C1:C6, C2:C10, Cys¹-Cys²-Glu³-Tyr⁴-Cys⁵-Cys⁶-Asn⁷-Pro⁸-Ala⁹-Cys¹⁰-Thr¹¹-Gly¹²- 60 C5:13 Cys¹³-dTyr¹⁴ SP-357 C1:C6, C2:C10, PEG3-Cys¹-Cys²-Glu³-Tyr⁴-Cys⁵-Cys⁶-Asn⁷-Pro⁸-Ala⁹-Cys¹⁰-Thr¹¹- 61 C5:13 Gly¹²-Cys¹³-Tyr¹⁴ SP-374 C3:C8, C4:C12, Asn¹-Phe²-Cys³-Cys⁴-Glu⁵-Thr⁶-Cys⁷-Cys⁸-Asn⁹-Pro¹⁰-Ala¹¹-Cys¹²- 62 C7:15 Thr¹³-Gly¹⁴-Cys¹⁵-Tyr¹⁶ SP-375 C3:C8, C4:C12, Asn¹-Phe²-Cys³-Cys⁴-Glu⁵-Ser⁶-Cys⁷-Cys⁸-Asn⁹-Pro¹⁰-Ala¹¹-Cys¹²- 63 C7:15 Thr¹³-Gly¹⁴-Cys¹⁵-dTyr¹⁶ SP-376 C3:C8, C4:C12, dAsn¹-Phe²-Cys³-Cys⁴-Glu⁵-Ser⁶-Cys⁷-Cys⁸-Asn⁹-Pro¹⁰-Ala¹¹-Cys¹²- 64 C7:15 Thr¹³-Gly¹⁴-Cys¹⁵-Tyr¹⁶ SP-377 C3:C8, C4:C12, dAsn¹-Phe²-Cys³-Cys⁴-Glu⁵-Ser⁶-Cys⁷-Cys⁸-Asn⁹-Pro¹⁰-Ala¹¹-Cys¹²- 65 C7:15 Thr¹³-Gly¹⁴-Cys¹⁵-dTyr¹⁶ SP-378 C3:C8, C4:C12,  Asn¹-Phe²-Cys³-Cys⁴-Glu⁵-Thr⁶-Cys⁷-Cys⁸-Asn⁹-Pro¹⁰-Ala¹¹-Cys¹²- 66 C7:15 Thr¹³-Gly¹⁴-Cys¹⁵-dTyr¹⁶ SP-379 C3:C8, C4:C12, dAsn¹-Phe²-Cys³-Cys⁴-Glu⁵-Thr⁶-Cys⁷-Cys⁸-Asn⁹-Pro¹⁰-Ala¹¹-Cys¹²- 67 C7:15 Thr¹³-Gly¹⁴-Cys¹⁵-Tyr¹⁶ SP-380 C3:C8, C4:C12, dAsn¹-Phe²-Cys³-Cys⁴-Glu⁵-Thr⁶-Cys⁷-Cys⁸-Asn⁹-Pro¹⁰-Ala¹¹-Cys¹²- 68 C7:15 Thr¹³-Gly¹⁴-Cys¹⁵-dTyr¹⁶ SP-381 C3:C8, C4:C12, Asn¹-Phe²-Cys³-Cys⁴-Glu⁵-Phe⁶-Cys⁷-Cys⁸-Asn⁹-Pro¹⁰-Ala¹¹-Cys¹²- 69 C7:15 Thr¹³-Gly¹⁴-Cys¹⁵-dTyr¹⁶ SP-382 C3:C8, C4:C12, dAsn¹-Phe²-Cys³-Cys⁴-Glu⁵-Phe⁶-Cys⁷-Cys⁸-Asn⁹-Pro¹⁰-Ala¹¹-Cys¹²- 70 C7:15 Thr¹³-Gly¹⁴-Cys¹⁵-Tyr¹⁶ SP-383 C3:C8, C4:C12, dAsn¹-Phe²-Cys³-Cys⁴-Glu⁵-Phe⁶-Cys⁷-Cys⁸-Asn⁹-Pro¹⁰-Ala¹¹-Cys¹²- 71 C7:15 Thr¹³-Gly¹⁴-Cys¹⁵-dTyr¹⁶ SP384 C1:C6, C2:C10, Cys¹-Cys²-Glu³-Tyr⁴-Cys⁵-Cys⁶-Asn⁷-Pro⁸-Ala⁹-Cys¹⁰-Thr¹¹-Gly¹²- 72 C5:13 Cys¹³-Tyr¹⁴-PEG3 N14 C1:C6, C2:C10, PEG3-Cys¹-Cys²-Glu³-Tyr⁴-Cys⁵-Cys⁶-Asn⁷-Pro⁸-Ala⁹-Cys¹⁰-Thr¹¹- 73 C5:13 Gly¹²-Cys¹³-PEG3 N15 C1:C6, C2:C10, PEG3-Cys¹-Cys²-Glu³-Tyr⁴-Cys⁵-Cys⁶-Asn⁷-Pro⁸-Ala⁹-Cys¹⁰-Thr¹¹- 74 C5:13 Gly¹²-Cys¹³ N16 C1:C6, C2:C10, Cys¹-Cys²-Glu³-Tyr⁴-Cys⁵-Cys⁶-Asn⁷-Pro⁸-Ala⁹-Cys¹⁰-Thr¹¹-Gly¹²- 75 C5:13 Cys¹³-PEG3 N17 C3:C8, C4:C12, PEG3- Asn¹-Phe²-Cys³-Cys⁴-Glu⁵-Ser⁶-Cys⁷-Cys⁸-Asn⁹-Pro¹⁰-Ala¹¹- 76 C7:15 Cys¹²-Thr¹³-Gly¹⁴-Cys¹⁵-Tyr¹⁶-PEG3 N18 C3:C8, C4:C12, PEG3- Asn¹-Phe²-Cys³-Cys⁴-Glu⁵-Ser⁶-Cys⁷-Cys⁸-Asn⁹-Pro¹⁰-Ala¹¹- 77 C7:15 Cys¹²-Thr¹³-Gly¹⁴-Cys¹⁵-Tyr¹⁶ N19 C3:C8, C4:C12, Asn¹-Phe²-Cys³-Cys⁴-Glu⁵-Ser⁶-Cys⁷-Cys⁸-Asn⁹-Pro¹⁰-Ala¹¹-Cys¹²- 78 C7:15 Thr¹³-Gly¹⁴-Cys¹⁵-Tyr¹⁶-PEG3 N20 C3:C8, C4:C12, PEG3-Asn¹-Phe²-Cys³-Cys⁴-Glu⁵-Phe⁶-Cys⁷-Cys⁸-Asn⁹-Pro¹⁰-Ala¹¹- 79 C7:15 Cys¹²-Thr¹³-Gly¹⁴-Cys¹⁵-Tyr¹⁶-PEG3 N21 C3:C8, C4:C12, PEG3-Asn¹-Phe²-Cys³-Cys⁴-Glu⁵-Phe⁶-Cys⁷-Cys⁸-Asn⁹-Pro¹⁰-Ala¹¹- 80 C7:15 Cys¹²-Thr¹³-Gly¹⁴-Cys¹⁵-Tyr¹⁶ N22 C3:C8, C4:C12, Asn¹-Phe²-Cys³-Cys⁴-Glu⁵-Phe⁶-Cys⁷-Cys⁸-Asn⁹-Pro¹⁰-Ala¹¹-Cys¹²- 81 C7:15 Thr¹³-Gly¹⁴-Cys¹⁵-Tyr¹⁶-PEG3 N23 C3:C8, C4:C12, PEG3- Asn¹-Phe²-Cys³-Cys⁴-Glu⁵-Tyr⁶-Cys⁷-Cys⁸-Asn⁹-Pro¹⁰-Ala¹¹- 82 C7:15 Cys¹²-Thr¹³-Gly¹⁴-Cys¹⁵-Tyr¹⁶-PEG3 N24 C3:C8, C4:C12, PEG3- Asn¹-Phe²-Cys³-Cys⁴-Glu⁵-Tyr⁶-Cys⁷-Cys⁸-Asn⁹-Pro¹⁰-Ala¹¹- 83 C7:15 Cys¹²-Thr¹³-Gly¹⁴-Cys¹⁵-Tyr¹⁶ N25 C3:C8, C4:C12, Asn¹-Phe²-Cys³-Cys⁴-Glu⁵-Tyr⁶-Cys⁷-Cys⁸-Asn⁹-Pro¹⁰-Ala¹¹-Cys¹²- 84 C7:15 Thr¹³-Gly¹⁴-Cys¹⁵-Tyr¹⁶-PEG3 N26 C1:C6, C2:C10, Cys¹-Cys²-Glu³-Ser⁴-Cys⁵-Cys⁶-Asn⁷-Pro⁸-Ala⁹-Cys¹⁰-Thr¹¹-Gly¹²- 85 C5:13 Cys¹³-Tyr¹⁴ N27 C1:C6, C2:C10, Cys¹-Cys²-Glu³-Phe⁴-Cys⁵-Cys⁶-Asn⁷-Pro⁸-Ala⁹-Cys¹⁰-Thr¹¹-Gly¹²- 86 C5:13 Cys¹³-Tyr¹⁴ N28 C1:C6, C2:C10, Cys¹-Cys²-Glu³-Ser⁴-Cys⁵-Cys⁶-Asn⁷-Pro⁸-Ala⁹-Cys¹⁰-Thr¹¹-Gly¹²- 87 C5:13 Cys¹³- N29 C1:C6, C2:C10, Cys¹-Cys²-Glu³-Phe⁴-Cys⁵-Cys⁶-Asn⁷-Pro⁸-Ala⁹-Cys¹⁰-Thr¹¹-Gly¹²- 88 C5:13 Cys¹³ N30 1:6, 2:10, 5:13 Pen¹-Pen²-Glu³-Tyr⁴-Pen⁵-Pen⁶-Asn⁷-Pro⁸-Ala⁹-Pen¹⁰-Thr¹¹-Gly¹²- 89 Pen¹³-Tyr¹⁴ N31 1:6, 2:10, 5:13 Pen¹-Pen²-Glu³-Tyr⁴-Pen⁵-Pen⁶-Asn⁷-Pro⁸-Ala⁹-Pen¹⁰-Thr¹¹-Gly¹²- 90 Pen¹³ Formula X C9:C14, C10:C18, Xaa¹-Xaa²-Xaa³-Xaa⁴-Xaa⁵-Xaa⁶-Asn⁷-Tyr⁸-Cys⁹-Cys¹⁰Xaa¹¹-Tyr¹²- 91 C13:21 Cys¹³-Cys¹⁴Xaa¹⁵Xaa¹⁶-Xaa¹⁷-Cys¹⁸-Xaa¹⁹-Xaa²⁰-Cys²¹-Xaa²² Formula XI C9:C14, C10:C18, Xaa¹-Xaa²-Xaa³-Xaa⁴-Xaa⁵-Xaa⁶-Asn⁷-Phe⁸-Cys⁹-Cys¹⁰-Xaa¹¹-Phe¹²- 92 C13:21 Cys¹³-Cys¹⁴-Xaa¹⁵-Xaa¹⁶-Xaa¹⁷-Cys¹⁸-Xaa¹⁹-Xaa²⁰-Cys²¹-Xaa²² Formula XII C3:C8, C4:C12, Asn¹-Phe²-Cys³-Cys⁴-Xaa⁵-Phe⁶-Cys⁷-Cys⁸-Xaa⁹-Xaa¹⁰-Xaa¹¹-Cys¹²- 93 C7:15 Xaa³-Xaa¹⁴-Cys¹⁵-Xaa¹⁶ Formula 3:8, 4:12, C:15 Asn¹-Phe²-Pen³-Cys⁴-Xaa⁵-Phe⁶-Cys⁷Pen⁸-Xaa⁹-Xaa¹⁰-Xaa¹¹-Cys12- 94 XIII Xaa¹³-Xaa¹⁴-Cys¹⁵-Xaa¹⁶ Formula 3:8, 4:12, 7:15 Asn¹-Phe²-Maa³-Maa⁴-Xaa⁵-Xaa⁶-Maa⁷-Maa⁸-Xaa⁹-Xaa¹⁰-Xaa¹¹-Maa¹²- 95 XIV Xaa¹³-Xaa¹⁴-Maa¹⁵-Xaa¹⁶ Formula XV 1:6, 2:10, 5:13 Maa¹-Maa²-Glu³-Xaa⁴-Maa⁵-Maa⁶-Asn⁷-Pro⁸-Ala⁹-Maa¹⁰-Thr¹¹-Gly¹²- 96 Maa¹³-Tyr¹⁴ Formula 1:6, 2:10, 5:13 Maa¹-Maa²-Glu³-Xaa⁴- Maa⁵-Maa⁶-Asn⁷-Pro⁸-Ala⁹-Maa¹⁰-Thr¹¹-Gly¹²- 97 XVI Maa¹³- Formula 1:6, 2:10, 5:13 Xaa_(n3)-Maa¹-Maa²-Xaa³-Xaa⁴-Maa⁵-Maa⁶-Xaa⁷-Xaa⁸-Xaa⁹-Maa¹⁰-Xaa¹¹- 98 XVII Xaa¹²-Maa¹³-Xaa_(n2)

TABLE III GCRA Peptides Position of SEQ ID Name Disulfide bonds Structure NO: SP-363 C4:C12, C7:C15 dAsn¹-Asp²-Glu³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Val⁸-Asn⁹-Val¹⁰-Ala¹¹-Cys¹²-Thr¹³-  99 AMIDE¹⁶Gly¹⁴-Cys¹⁵-dLeu- SP-364 C4:C12, C7:C15 dAsn¹-Asp²-Glu³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Val⁸-Asn⁹-Val¹⁰-Ala¹¹-Cys¹²-Thr¹³- 100 Gly¹⁴-Cys¹⁵-dSer¹⁶ SP-365 C4:C12, C7:C15 dAsn¹-Asp²-Glu³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Val⁸-Asn⁹-Val¹⁰-Ala¹¹-Cys¹²-Thr¹³- 101 Gly¹⁴-Cys¹⁵-dSer-AMIDE¹⁶ SP-366 C4:C12, C7:C15 dAsn¹-Asp²-Glu³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Val⁸-Asn⁹-Val¹⁰-Ala¹¹-Cys¹²-Thr¹³- 102 Gly¹⁴-Cys¹⁵-dTyr¹⁶ SP-367 C4:C12, C7:C15 dAsn¹-Asp²-Glu³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Val⁸-Asn⁹-Val¹⁰-Ala¹¹-Cys¹²-Thr¹³- 103 Gly¹⁴-Cys¹⁵-dTyr-AMIDE¹⁶ SP-373 C4:C12, C7:C15 Pyglu¹-Asp²-Glu³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Val⁸-Asn⁹-Val¹⁰-Ala¹¹-Cys¹²-Thr¹³- 104 Gly¹⁴-Cys¹⁵-dLeu-AMIDE¹⁶ SP-304 C4:C12, C7:C15 PEG3-Asn¹-Asp²-Glu³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Val⁸-Asn⁹-Val¹⁰-Ala¹¹-Cys¹²- 105 diPEG Thr¹³-Gly¹⁴-Cys¹⁵-Leu¹⁶-PEG3 SP-304 C4:C12, C7:C15 PEG3-Asn¹-Asp²-Glu³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Val⁸-Asn⁹-Val¹⁰-Ala¹¹-Cys¹²- 106 N-PEG Thr¹³-Gly¹⁴-Cys¹⁵-Leu¹⁶ SP-304 C4:C12, C7:C15 Asn¹-Asp²-Glu³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Val⁸-Asn⁹-Val¹⁰-Ala¹¹-Cys¹²-Thr¹³- 107 C-PEG Gly¹⁴-Cys¹⁵-Leu¹⁶⁻PEG3

TABLE IV SP-304 Analogs, Uroguanylin, and Uroguanylin Analogs Position of SEQ Disulfide ID Name bonds Structure NO Formula C4:C12, Xaa¹-Xaa²-Xaa³-Maa⁴-Xaa⁵-Xaa⁶-Maa⁷-Xaa⁸-Xaa⁹-Xaa¹⁰-Xaa¹¹-Maa¹²-Xaa¹³-Xaa¹⁴- 108 XVIII C7:C15 Maa¹⁵-Aaa¹⁶ Uro- C4:C12, Asn¹-Asp²-Asp³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Val⁸-Asn⁹-Val¹⁰-Ala¹¹-Cys¹²-Thr¹³-Gly¹⁴- 109 guanylin C7:C15 Cys¹⁵-Leu¹⁶ N32 C4:C12, Glu¹-Asp²-Asp³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Val⁸-Asn⁹-Val¹⁰-Ala¹¹-Cys¹²-Thr¹³-Gly¹⁴- 110 C7:C15 Cys¹⁵-Leu¹⁶ N33 C4:C12, Glu¹-Asp²-Glu³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Val⁸-Asn⁹-Val¹⁰-Ala¹¹-Cys¹²-Thr¹³-Gly¹⁴- 111 C7:C15 Cys¹⁵-Leu¹⁶ N34 C4:C12, Glu¹-Glu²-Asp³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Val⁸-Asn⁹-Val¹⁰-Ala¹¹-Cys¹²-Thr¹³-Gly¹⁴- 112 C7:C15 Cys¹⁵-Leu¹⁶ N35 C4:C12, Glu¹-Glu²-Glu³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Val⁸-Asn⁹-Val¹⁰-Ala¹¹-Cys¹²-Thr¹³-Gly¹⁴- 113 C7:C15 Cys¹⁵-Leu¹⁶ N36 C4:C12, Asp¹-Asp²-Asp³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Val⁸-Asn⁹-Val¹⁰-Ala¹¹-Cys¹²-Thr¹³-Gly¹⁴- 114 C7:C15 Cys¹⁵-Leu¹⁶ N37 C4:C12, Asp¹-Asp²-Glu³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Val⁸-Asn⁹-Val¹⁰-Ala¹¹-Cys¹²-Thr¹³-Gly¹⁴- 115 C7:C15 Cys¹⁵-Leu¹⁶ N38 C4:C12, Asp¹-Glu²-Asp³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Val⁸-Asn⁹-Val¹⁰-Ala¹¹-Cys¹²-Thr¹³-Gly¹⁴- 116 C7:C15 Cys¹⁵-Leu¹⁶ N39 C4:C12, Asp¹-Glu²-Glu³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Val⁸-Asn⁹-Val¹⁰-Ala¹¹-Cys¹²-Thr¹³-Gly¹⁴- 117 C7:C15 Cys¹⁵-Leu¹⁶ N40 C4:C12, Gln¹-Asp²-Asp³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Val⁸-Asn⁹-Val¹⁰-Ala¹¹-Cys¹²-Thr¹³-Gly¹⁴- 118 C7:C15 Cys¹⁵-Leu¹⁶ N41 C4:C12, Gln¹-Asp²-Glu³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Val⁸-Asn⁹-Val¹⁰-Ala¹¹-Cys¹²-Thr¹³-Gly¹⁴- 119 C7:C15 Cys¹⁵-Leu¹⁶ N42 C4:C12, Gln¹-Glu²-Asp³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Val⁸-Asn⁹-Val¹⁰-Ala¹¹-Cys¹²-Thr¹³-Gly¹⁴- 120 C7:C15 Cys¹⁵-Leu¹⁶ N43 C4:C12, Gln¹-Glu²-Glu³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Val⁸-Asn⁹-Val¹⁰-Ala¹¹-Cys¹²-Thr¹³-Gly¹⁴- 121 C7:C15 Cys¹⁵-Leu¹⁶ N44 C4:C12, Lys¹-Asp²-Asp³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Val⁸-Asn⁹-Val¹⁰-Ala¹¹-Cys¹²-Thr¹³-Gly¹⁴- 122 C7:C15 Cys¹⁵-Leu¹⁶ N45 C4:C12, Lys¹-Asp²-Glu³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Val⁸-Asn⁹-Val¹⁰-Ala¹¹-Cys¹²-Thr¹³-Gly¹⁴- 123 C7:C15 Cys¹⁵-Leu¹⁶ N46 C4:C12, Lys¹-Glu²-Asp³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Val⁸-Asn⁹-Val¹⁰-Ala¹¹-Cys¹²-Thr¹³-Gly¹⁴- 124 C7:C15 Cys¹⁵-Leu¹⁶ N47 C4:C12, Lys¹-Glu²-Glu³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Val⁸-Asn⁹-Val¹⁰-Ala¹¹-Cys¹²-Thr¹³-Gly¹⁴- 125 C7:C15 Cys¹⁵-Leu¹⁶ N48 C4:C12, Glu¹-Asp²-Asp³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Val⁸-Asn⁹-Val¹⁰-Ala¹¹-Cys¹²-Thr¹³-Gly¹⁴- 126 C7:C15 Cys¹⁵-Ser¹⁶ N49 C4:C12, Glu¹-Asp²-Glu³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Val⁸-Asn⁹-Val¹⁰-Ala¹¹-Cys¹²-Thr¹³-Gly¹⁴- 127 C7:C15 Cys¹⁵-Ser¹⁶ N50 C4:C12, Glu¹-Glu²-Asp³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Val⁸-Asn^(9+l-Val10)-Ala¹¹-Cys¹²-Thr¹³-Gly¹⁴- 128 C7:C15 Cys¹⁵-Ser¹⁶ N51 C4:C12, Glu¹-Glu²-Glu³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Val⁸-Asn⁹-Val¹⁰-Ala¹¹-Cys¹²-Thr¹³-Gly¹⁴- 129 C7:C15 Cys¹⁵-Ser¹⁶ N52 C4:C12, Asp¹-Asp²-Asp³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Val⁸-Asn⁹-Val¹⁰-Ala¹¹-Cys¹²-Thr¹³-Gly¹⁴- 130 C7:C15 Cys¹⁵-Ser¹⁶ N53 C4:C12, Asp¹-Asp²-Glu³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Val⁸-Asn⁹-Val¹⁰-Ala^(11-Cys12)-Thr¹³-Gly¹⁴- 131 C7:C15 Cys¹⁵Ser¹⁶ N54 C4:C12, Asp¹-Glu²-Asp³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Val⁵-Asn⁹-Val¹⁰-Ala¹¹-Cys¹²-Thr¹³-Gly¹⁴- 132 C7:C15 Cys¹⁵-Ser¹⁶ N55 C4:C12, Asp¹-Glu²-Glu³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Val⁸-Asn⁹-Val¹⁰-Ala¹¹-Cys¹²-Thr¹³-Gly¹⁴- 133 C7:C15 Cys¹⁵-Ser¹⁶ N56 C4:C12, Gln¹-Asp²-Asp³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Val⁸-Asn⁹-Val¹⁰-Ala¹¹-Cys¹²-Thr¹³-Gly¹⁴- 134 C7:C15 Cys¹⁵-Ser¹⁶ N57 C4:C12, Gln¹-Asp²-Glu³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Val⁸-Asn⁹-Val¹⁰-Ala¹¹-Cys¹²-Thr¹³-Gly¹⁴- 135 C7:C15 Cys¹⁵-Ser¹⁶ N58 C4:C12, Gln¹-Glu²-Asp³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Val⁸-Asn⁹-Val¹⁰-Ala¹¹-Cys¹²-Thr¹³-Gly¹⁴- 136 C7:C15 Cys¹⁵-Ser¹⁶ N59 C4:C12, Gln¹-Glu²-Glu³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Val⁸-Asn⁹-Val¹⁰-Ala¹¹-Cys¹²-Thr¹³-Gly¹⁴- 137 C7:C15 Cys¹⁵-Ser¹⁶ N60 C4:C12, Lys¹-Asp²-Asp³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Val⁸-Asn⁹-Val¹⁰-Ala¹¹-Cys¹²-Thr¹³-Gly¹⁴- 138 C7:C15 Cys¹⁵-Ser¹⁶ N61 C4:C12, Lys¹-Asp²-Glu³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Val⁸-Asn⁹-Val¹⁰-Ala¹¹-Cys¹²-Thr¹³-Gly¹⁴- 139 C7:C15 Cys¹⁵-Ser¹⁶ N62 C4:C12, Lys¹-Glu²-Asp³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Val⁸-Asn⁹-Val¹⁰-Ala¹¹-Cys¹²-Thr¹³-Gly¹⁴- 140 C7:C15 Cys¹⁵-Ser¹⁶ N63 C4:C12, Lys¹-Glu²-Glu³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Val⁸-Asn⁹-Val¹⁰-Ala¹¹-Cys¹²-Thr¹³-Gly¹⁴- 141 C7:C15 Cys¹⁵-Ser¹⁶ N65 C4:C12, Glu¹-Asp²-Asp³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Ile⁸-Asn⁹-Met¹⁰-Ala¹¹-Cys¹²-Thr¹³-Gly¹⁴- 142 C7:C15 Cys¹⁵-Leu¹⁶ N66 C4:C12, Glu¹-Asp²-Glu³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Ile⁸-Asn⁹-Met¹⁰-Ala¹¹-Cys¹²-Thr¹³-Gly¹⁴- 143 C7:C15 Cys¹⁵-Leu¹⁶ N67 C4:C12, Glu¹-Glu²-Asp³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Ile⁸-Asn⁹-Met¹⁰-Ala¹¹-Cys¹²-Thr¹³-Gly¹⁴- 144 C7:C15 Cys¹⁵-Leu¹⁶ N68 C4:C12, Glu¹-Glu²-Glu³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Ile⁸-Asn⁹-Met¹⁰-Ala¹¹-Cys¹²-Thr¹³-Gly¹⁴- 145 C7:C15 Cys¹⁵-Leu¹⁶ N69 C4:C12, Asp¹-Asp²-Asp³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Ile⁸-Asn⁹-Met¹⁰-Ala¹¹-Cys¹²-Thr¹³-Gly¹⁴- 146 C7:C15 Cys¹⁵-Leu¹⁶ N70 C4:C12, Asp¹-Asp²-Glu³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Ile⁸-Asn⁹-Met¹⁰-Ala¹¹-Cys¹²-Thr¹³-Gly¹⁴- 147 C7:C15 Cys¹⁵-Leu¹⁶ N71 C4:C12, Asp¹-Glu²-Asp³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Ile⁸-Asn⁹-Met¹⁰-Ala¹¹-Cys¹²-Thr¹³-Gly¹⁴- 148 C7:C15 Cys¹⁵-Leu¹⁶ N72 C4:C12, Asp¹-Glu²-Glu³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Ile⁸-Asn⁹-Met¹⁰-Ala¹¹-Cys¹²-Thr¹³-Gly¹⁴- 149 C7:C15 Cys¹⁵-Leu¹⁶ N73 C4:C12, Gln¹-Asp²-Asp³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Ile⁸-Asn⁹-Met¹⁰-Ala¹¹-Cys¹²-Thr¹³-Gly¹⁴- 150 C7:C15 Cys¹⁵-Leu¹⁶ N74 C4:C12, Gln¹-Asp²-Glu³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Ile⁸-Asn⁹-Met¹⁰-Ala¹¹-Cys¹²-Thr¹³-Gly¹⁴- 151 C7:C15 Cys¹⁵-Leu¹⁶ N75 C4:C12, Gln¹-Glu²-Asp³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Ile⁸-Asn⁹-Met¹⁰-Ala¹¹-Cys¹²-Thr¹³-Gly¹⁴- 152 C7:C15 Cys¹⁵-Leu¹⁶ N76 C4:C12, Gln¹-Glu²-Glu³-Cys⁴-Glu⁵-Leu⁶-Cys7-Ile⁸-Asn⁹-Met¹⁰-Ala¹¹-Cys¹²-Thr¹³-Gly¹⁴- 153 C7:C15 Cys¹⁵-Leu¹⁶ N77 C4:C12, Lys¹-Asp²-Asp³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Ile⁸-Asn⁹-Met¹⁰-Ala¹¹-Cys¹²-Thr¹³-Gly¹⁴- 154 C7:C15 Cys¹⁵-Leu¹⁶ N78 C4:C12, Lys¹-Asp²-Glu³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Ile⁸-Asn⁹-Met¹⁰-Ala¹¹-Cys¹²-Thr¹³-Gly¹⁴- 155 C7:C15 Cys¹⁵-Leu¹⁶ N79 C4:C12, Lys¹-Glu²-Asp³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Ile⁸-Asn⁹-Met¹⁰-Ala¹¹-Cys¹²-Thr¹³-Gly¹⁴- 156 C7:C15 Cys¹⁵-Leu¹⁶ N80 C4:C12, Lys¹-Glu²-Glu³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Ile⁸-Asn⁹-Met¹⁰-Ala¹¹-Cys¹²-Thr¹³-Gly¹⁴- 157 C7:C15 Cys¹⁵-Leu¹⁶ N81 C4:C12, Glu¹-Asp²-Asp³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Ile⁸-Asn⁹-Met¹⁰-Ala¹¹-Cys¹²-Thr¹³-Gly¹⁴- 158 C7:C15 Cys¹⁵-Ser¹⁶ N82 C4:C12, Glu¹-Asp²-Glu³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Ile⁸-Asn⁹-Met¹⁰-Ala¹¹-Cys¹²-Thr¹³-Gly¹⁴- 159 C7:C15 Cys¹⁵-Ser¹⁶ N83 C4:C12, Glu¹-Glu²-Asp³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Ile⁸-Asn⁹-Met¹⁰-Ala¹¹-Cys¹²-Thr¹³-Gly¹⁴- 160 C7:C15 Cys¹⁵-Ser¹⁶ N84 C4:C12, Glu¹-Glu²-Glu³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Ile⁸-Asn⁹-Met¹⁰-Ala¹¹-Cys¹²-Thr¹³-Gly¹⁴- 161 C7:C15 Cys¹⁵-Ser¹⁶ N85 C4:C12, Asp¹-Asp²-Asp³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Ile⁸-Asn⁹-Met¹⁰-Ala¹¹-Cys¹²-Thr¹³-Gly¹⁴- 162 C7:C15 Cys¹⁵-Ser¹⁶ N86 C4:C12, Asp¹-Asp²-Glu³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Ile⁸-Asn⁹-Met¹⁰-Ala¹¹-Cys¹²-Thr¹³-Gly¹⁴- 163 C7:C15 Cys¹⁵-Ser¹⁶ N87 C4:C12, Asp¹-Glu²-Asp³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Ile⁸-Asn⁹-Met¹⁰-Ala¹¹-Cys¹²-Thr¹³-Gly¹⁴- 164 C7:C15 Cys¹⁵-Ser¹⁶ N88 C4:C12, Asp¹-Glu²-Glu³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Il⁸-Asn⁹-Met¹⁰-Ala¹¹-Cys¹²-Thr¹³-Gly¹⁴- 165 C7:C15 Cys¹⁵-Ser¹⁶ N89 C4:C12, Gln¹-Asp²-Asp³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Ile⁸-Asn⁹-Met¹⁰-Ala¹¹-Cys¹²-Thr¹³-Gly¹⁴- 166 C7:C15 Cys¹⁵-Ser¹⁶ N90 C4:C12, Gln¹-Asp²-Glu³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Ile⁸-Asn⁹-Met¹⁰-Ala¹¹-Cys¹²-Thr¹³-Gly¹⁴- 167 C7:C15 Cys¹⁵-Ser¹⁶ N91 C4:C12, Gln¹-Glu²-Asp³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Ile⁸-Asn⁹-Met¹⁰-Ala¹¹-Cys¹²-Thr¹³-Gly¹⁴- 168 C7:C15 Cys¹⁵-Ser¹⁶ N92 C4:C12, Gln¹-Glu²-Glu³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Ile⁸-Asn⁹-Met¹⁰-Ala¹¹-Cys¹²-Thr¹³-Gly¹⁴- 169 C7:C15 Cys¹⁵-Ser¹⁶ N93 C4:C12, Lys¹-Asp²-Asp³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Ile⁸-Asn⁹-Met¹⁰-Ala¹¹-Cys¹²-Thr¹³-Gly¹⁴- 170 C7:C15 Cys¹⁵-Ser¹⁶ N94 C4:C12, Lys¹-Asp²-Glu³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Ile⁸-Asn⁹-Met¹⁰-Ala¹¹-Cys¹²-Thr¹³-Gly¹⁴- 171 C7:C15 Cys¹⁵-Ser¹⁶ N95 C4:C12, Lys¹-Glu²-Asp³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Ile⁸-Asn⁹-Met¹⁰-Ala¹¹-Cys¹²-Thr¹³-Gly¹⁴- 172 C7:C15 Cys¹⁵-Ser¹⁶ N96 C4:C12, Lys¹-Glu²-Glu³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Ile⁸-Asn⁹-Met¹⁰-Ala¹¹-Cys¹²-Thr¹³-Gly¹⁴- 173 C7:C15 Cys¹⁵-Ser¹⁶

TABLE V Guanylin and Analogs Position of SEQ ID Name Disulfide bonds Structure NO Formula 4:12,7:15 Xaa¹-Xaa²-Xaa³-Maa⁴-Xaa⁵-Xaa⁶-Maa⁷-Xaa⁸-Xaa⁹-Xaa¹⁰-Xaa¹¹-Maa¹²-Xaa¹³- 174 XIX Xaa¹⁴-Maa¹⁵ Guanylin C4:C12, C7:C15 Ser¹-His²-Thr³-Cys⁴-Glu⁵-Ile⁶-Cys⁷-Ala⁸-Phe⁹-Ala¹⁰-Ala¹¹-Cys¹²-Ala¹³- 175 Gly¹⁴-Cys¹⁵ N97 C4:C12, C7:C15 Ser¹-His²-Thr³-Cys⁴-Glu⁵-Ile⁶-Cys⁷-Ala⁸-Asn⁹-Ala¹⁰-Ala¹¹-Cys¹²-Ala¹³- 176 Gly¹⁴-Cys¹⁵ N98 C4:C12, C7:C15 Ser¹-His²-Thr³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Ala⁸-Asn⁹-Ala¹⁰-Ala¹¹-Cys¹²-Ala¹³- 177 Gly¹⁴-Cys¹⁵ N99 C4:C12, C7:C15 Ser¹-His²-Thr³-Cys⁴-Glu⁵-Val⁶-Cys⁷-Ala⁸-Asn⁹-Ala¹⁰-Ala¹¹-Cys¹²-Ala¹³- 178 Gly¹⁴-Cys¹⁵ N100 C4:C12, C7:C15 Ser¹-His²-Thr³-Cys⁴-Glu⁵-Tyr⁶-Cys⁷-Ala⁸-Asn⁹-Ala¹⁰-Ala¹¹-Cys¹²-Ala¹³- 179 Gly¹⁴-Cys¹⁵ N101 C4:C12, C7:C15 Ser¹-His²-Thr³-Cys⁴-Glu⁵-Ile⁶-Cys⁷-Ala⁸-Asn⁹-Ala¹⁰-Ala¹¹-Cys¹²-Ala¹³- 180 Gly¹⁴-Cys¹⁵ N102 C4:C12, C7:C15 Ser¹-His²-Thr³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Ala⁸-Asn⁹-Ala¹⁰-Ala¹¹-Cys¹²-Ala¹³- 181 Gly¹⁴-Cys¹⁵ N103 C4:C12, C7:C15 Ser¹-His²-Thr³-Cys⁴-Glu⁵-Val⁶-Cys⁷-Ala⁸-Asn⁹-Ala¹⁰-Ala¹¹-Cys¹²-Ala¹³- 182 Gly¹⁴-Cys¹⁵ N104 C4:C12, C7:C15 Ser¹-His²-Thr³-Cys⁴-Glu⁵-Tyr⁶-Cys⁷-Ala⁸-Asn⁹-Ala¹⁰-Ala¹¹-Cys¹²-Ala¹³- 183 Gly¹⁴-Cys¹⁵ N105 C4:C12, C7:C15 Ser¹-His²-Thr³-Cys⁴-Glu⁵-Ile⁶-Cys⁷-Ala⁸-Asn⁹-Ala¹⁰-Ala¹¹-Cys¹²-Ala¹³- 184 Gly¹⁴-Cys¹⁵ N106 C4:C12, C7:C15 Ser¹-His²-Thr³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Ala⁸-Asn⁹-Ala¹⁰-Ala¹¹-Cys¹²-Ala¹³- 185 Gly¹⁴-Cys¹⁵ N107 C4:C12, C7:C15 Ser¹-His²-Thr³-Cys⁴-Glu⁵-Val⁶-Cys⁷-Ala⁸-Asn⁹-Ala¹⁰-Ala¹¹-Cys¹²-Ala¹³- 186 Gly¹⁴-Cys¹⁵ N108 C4:C12, C7:C15 Ser¹-His²-Thr³-Cys⁴-Glu⁵-Tyr⁶-Cys⁷-Ala⁸-Asn⁹-Ala¹⁰-Ala¹¹-Cys¹²-Ala¹³- 187 Gly¹⁴-Cys¹⁵ N109 C4:C12, C7:C15 Ser¹-His²-Thr³-Cys⁴-Glu⁵-Ile⁶-Cys⁷-Ala⁸-Asn⁹-Ala¹⁰-Ala¹¹-Cys¹²-Ala¹³- 188 Gly¹⁴-Cys¹⁵ N110 C4:C12, C7:C15 Ser¹-His²-Thr³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Ala⁸-Asn⁹-Ala¹⁰-Ala¹¹-Cys¹²-Ala¹³- 189 Gly¹⁴-Cys¹⁵ N111 C4:C12, C7:C15 Ser¹-His²-Thr³-Cys⁴-Glu⁵-Val⁶-Cys⁷-Ala⁸-Asn⁹-Ala¹⁰-Ala¹¹-Cys¹²-Ala¹³- 190 Gly¹⁴-Cys¹⁵ N112 C4:C12, C7:C15 Ser¹-His²-Thr³-Cys⁴-Glu⁵-Tyr⁶-Cys⁷-Ala⁸-Asn⁹-Ala¹⁰-Ala¹¹-Cys¹²-Ala¹³- 191 Gly¹⁴-Cys¹⁵ N113 C4:C12, C7:C15 Asn¹-Asp²-Glu³-Cys⁴-Glu⁵-Ile⁶-Cys⁷-Ala⁸-Asn⁹-Ala¹⁰-Ala¹¹-Cys¹²-Ala¹³- 192 Gly¹⁴-Cys¹⁵ N114 C4:C12, C7:C15 Asn¹-Asp²-Glu³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Ala⁸-Asn⁹-Ala¹⁰-Ala¹¹-Cys¹²-Ala¹³- 193 Gly¹⁴-Cys¹⁵ N115 C4:C12, C7:C15 Asn¹-Asp²-Glu³-Cys⁴-Glu⁵-Val⁶-Cys⁷-Ala⁸-Asn⁹-Ala¹⁰-Ala¹¹-Cys¹²-Ala¹³- 194 Gly¹⁴-Cys¹⁵ N116 C4:C12, C7:C15 Asn¹-Asp²-Glu³-Cys⁴-Glu⁵-Tyr⁶-Cys⁷-Ala⁸-Asn⁹-Ala¹⁰-Ala¹¹-Cys¹²-Ala¹³- 195 Gly¹⁴-Cys¹⁵ N117 C4:C12, C7:C15 Asn¹-Asp²-Glu³-Cys⁴-Glu⁵-Ile⁶-Cys⁷-Ala⁸-Asn⁹-Ala¹⁰-Ala¹¹-Cys¹²-Ala¹³- 196 Gly¹⁴-Cys¹⁵ N118 C4:C12, C7:C15 Asn¹-Asp²-Glu³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Ala⁸-Asn⁹-Ala¹⁰-Ala¹¹-Cys¹²-Ala¹³- 197 Gly¹⁴-Cys¹⁵ N119 C4:C12, C7:C15 Asn¹-Asp²-Glu³-Cys⁴-Glu⁵-Val⁶-Cys⁷-Ala⁸-Asn⁹-Ala¹⁰-Ala¹¹-Cys¹²-Ala¹³- 198 Gly¹⁴-Cys¹⁵ N120 C4:C12, C7:C15 Asn¹-Asp²-Glu³-Cys⁴-Glu⁵-Tyr⁶-Cys⁷-Ala⁸-Asn⁹-Ala¹⁰-Ala¹¹-Cys¹²-Ala¹³- 199 Gly¹⁴-Cys¹⁵ N121 C4:C12, C7:C15 Asn¹-Asp²-Glu³-Cys⁴-Glu⁵-Ile⁶-Cys⁷-Ala⁸-Asn⁹-Ala¹⁰-Ala¹¹-Cys¹²-Ala¹³- 200 Gly¹⁴-Cys¹⁵ N122 C4:C12, C7:C15 Asn¹-Asp²-Glu³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Ala⁸-Asn⁹-Ala¹⁰-Ala¹¹-Cys¹²-Ala¹³- 201 Gly¹⁴-Cys¹⁵ N123 C4:C12, C7:C15 Asn¹-Asp²-Glu³-Cys⁴-Glu⁵-Val⁶-Cys⁷-Ala⁸-Asn⁹-Ala¹⁰-Ala¹¹-Cys¹²-Ala¹³- 202 Gly¹⁴-Cys¹⁵ N124 C4:C12, C7:C15 Asn¹-Asp²-Glu³-Cys⁴-Glu⁵-Tyr⁶-Cys⁷-Ala⁸-Asn⁹-Ala¹⁰-Ala¹¹-Cys¹²-Ala¹³- 203 Gly¹⁴-Cys¹⁵ N125 C4:C12, C7:C15 Asn¹-Asp²-Glu³-Cys⁴-Glu⁵-Ile⁶-Cys⁷-Ala⁸-Asn⁹-Ala¹⁰-Ala¹¹-Cys¹²-Ala¹³- 204 Gly¹⁴-Cys¹⁵ N126 C4:C12, C7:C15 Asn¹-Asp²-Glu³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Ala⁸-Asn⁹-Ala¹⁰-Ala¹¹-Cys¹²-Ala¹³- 205 Gly¹⁴-Cys¹⁵ N127 C4:C12, C7:C15 Asn¹-Asp²-Glu³-Cys⁴-Glu⁵-Val⁶-Cys⁷-Ala⁸-Asn⁹-Ala¹⁰-Ala¹¹-Cys¹²-Ala¹³- 206 Gly¹⁴-Cys¹⁵ N128 C4:C12, C7:C15 Asn¹-Asp²-Glu³-Cys⁴-Glu⁵-Tyr⁶-Cys⁷-Ala⁸-Asn⁹-Ala¹⁰-Ala¹¹-Cys¹²-Ala¹³- 207 Gly¹⁴-Cys¹⁵

TABLE VI Lymphoguanylin and Analogs Position of Disulfide SEQ Name bonds Structure ID NO Formula XX 4:12,7:15 Xaa¹-Xaa²-Xaa³-Maa⁴-Xaa⁵-Xaa⁶-Maa⁷-Xaa⁸-Xaa⁹-Xaa¹⁰-Xaa¹¹-Maa¹²-Xaa¹³- 208 Xaa¹⁴-Xaa_(a1) ¹⁵ Lymphoguanylin C4:C12 Gln¹-Glu²-Glu³-Cys⁴-Glu⁵-Leu⁶-Cys⁷-Ile⁸-Asn⁹-Met¹⁰-Ala¹¹-Cys¹²-Thr¹³- 209 Gly¹⁴-Tyr¹⁵ N129 C4:C12 Gln¹-Glu²-Glu³-Cys⁴-Glu⁵-Thr⁶-Cys⁷-Ile⁸-Asn⁹-Met¹⁰-Ala¹¹-Cys¹²-Thr¹³- 210 Gly¹⁴-Tyr¹⁵ N130 C4:C12 Gln¹-Asp²-Glu³-Cys⁴-Glu⁵-Thr⁶-Cys⁷-Ile⁸-Asn⁹-Met¹⁰-Ala¹¹-Cys¹²-Thr¹³- 211 Gly¹⁴-Tyr¹⁵ N131 C4:C12 Gln¹-Asp²-Asp³-Cys⁴-Glu⁵-Thr⁶-Cys⁷-Ile⁸-Asn⁹-Met¹⁰-Ala¹¹-Cys¹²-Thr¹³- 212 Gly¹⁴-Tyr¹⁵ N132 C4:C12 Gln¹-Glu²-Asp³-Cys⁴-Glu⁵-Thr⁶-Cys⁷-Ile⁸-Asn⁹-Met¹⁰-Ala¹¹-Cys¹²-Thr¹³- 213 Gly¹⁴-Tyr¹⁵ N133 C4:C12 Gln¹-Glu²-Glu³-Cys⁴-Glu⁵-Glu⁶-Cys⁷-Ile⁸-Asn⁹-Met¹⁰-Ala¹¹-Cys¹²-Thr¹³- 214 Gly¹⁴-Tyr¹⁵ N134 C4:C12 Gln¹-Asp²-Glu³-Cys⁴-Glu⁵-Glu⁶-Cys⁷-Ile⁸-Asn⁹-Met¹⁰-Ala¹¹-Cys¹²-Thr¹³- 215 Gly¹⁴-Tyr¹⁵ N135 C4:C12 Gln¹-Asp²-Asp³-Cys⁴-Glu⁵-Glu⁶-Cys⁷-Ile⁸-Asn⁹-Met¹⁰-Ala¹¹-Cys¹²-Thr¹³- 216 Gly¹⁴-Tyr¹⁵ N136 C4:C12 Gln¹-Glu²-Asp³-Cys⁴-Glu⁵-Glu⁶-Cys⁷-Ile⁸-Asn⁹-Met¹⁰-Ala¹¹-Cys¹²-Thr¹³- 217 Gly¹⁴-Tyr¹⁵ N137 C4:C12 Gln¹-Glu²-Glu³-Cys⁴-Glu⁵-Tyr⁶-Cys⁷-Ile⁸-Asn⁹-Met¹⁰-Ala¹¹-Cys¹²-Thr¹³- 218 Gly¹⁴-Tyr¹⁵ N138 C4:C12 Gln¹-Asp²-Glu³-Cys⁴-Glu⁵-Tyr⁶-Cys⁷-Ile⁸-Asn⁹-Met¹⁰-Ala¹¹-Cys¹²-Thr¹³- 219 Gly¹⁴-Tyr¹⁵ N139 C4:C12 Gln¹-Asp²-Asp³-Cys⁴-Glu⁵-Tyr⁶-Cys⁷-Ile⁸-Asn⁹-Met¹⁰-Ala¹¹-Cys¹²-Thr¹³- 220 Gly¹⁴-Tyr¹⁵ N140 C4:C12 Gln¹-Glu²-Asp³-Cys⁴-Glu⁵-Tyr⁶-Cys⁷-Ile⁸-Asn⁹-Met¹⁰-Ala¹¹-Cys¹²-Thr¹³- 221 Gly¹⁴-Tyr¹⁵ N141 C4:C12 Gln¹-Glu²-Glu³-Cys⁴-Glu⁵-Ile⁶-Cys⁷-Ile⁸-Asn⁹-Met¹⁰-Ala¹¹-Cys¹²-Thr¹³- 222 Gly¹⁴-Tyr¹⁵ N142 C4:C12 Gln¹-Asp²-Glu³-Cys⁴-Glu⁵-Ile⁶-Cys⁷-Ile⁸-Asn⁹-Met¹⁰-Ala¹¹-Cys¹²-Thr¹³- 223 Gly¹⁴-Tyr¹⁵ N143 C4:C12 Gln¹-Asp²-Asp³-Cys⁴-Glu⁵-Ile⁶-Cys⁷-Ile⁸-Asn⁹-Met¹⁰-Ala¹¹-Cys¹²-Thr¹³- 224 Gly¹⁴-Tyr¹⁵ N144 C4:C12 Gln¹-Glu²-Asp³-Cys⁴-Glu⁵-Ile⁶-Cys⁷-Ile⁸-Asn⁹-Met¹⁰-Ala¹¹-Cys¹²-Thr¹³- 225 Gly¹⁴-Tyr¹⁵ N145 C4:C12, Gln¹-Glu²-Glu³-Cys⁴-Glu⁵-Thr⁶-Cys⁷-Ile⁸-Asn⁹-Met¹⁰-Ala¹¹-Cys¹²-Thr¹³- 226 C7:C15 Gly¹⁴-Cys¹⁵-Ser¹⁶ N146 C4:C12, Gln¹-Asp²-Glu³-Cys⁴-Glu⁵-Thr⁶-Cys⁷-Ile⁸-Asn⁹-Met¹⁰-Ala¹¹-Cys¹²-Thr¹³- 227 C7:C15 Gly¹⁴-Cys¹⁵-Ser¹⁶ N147 C4:C12, Gln¹-Asp²-Asp³-Cys⁴-Glu⁵-Thr⁶-Cys⁷-Ile⁸-Asn⁹-Met¹⁰-Ala¹¹-Cys¹²-Thr¹³- 228 C7:C15 Gly¹⁴-Cys¹⁵-Ser¹⁶ N148 C4:C12, Gln¹-Glu²-Asp³-Cys⁴-Glu⁵-Thr⁶-Cys⁷-Ile⁸-Asn⁹-Met¹⁰-Ala¹¹-Cys¹²-Thr¹³- 229 C7:C15 Gly¹⁴-Cys¹⁵-Ser¹⁶ N149 C4:C12, Gln¹-Glu²-Glu³-Cys⁴-Glu⁵-Glu⁶-Cys⁷-Ile⁸-Asn⁹-Met¹⁰-Ala¹¹-Cys¹²-Thr¹³- 230 C7:C15 Gly¹⁴-Cys¹⁵-Ser¹⁶ N150 C4:C12, Gln¹-Asp²-Glu³-Cys⁴-Glu⁵-Glu⁶-Cys⁷-Ile⁸-Asn⁹-Met¹⁰-Ala¹¹-Cys¹²-Thr¹³- 231 C7:C15 Gly¹⁴-Cys¹⁵-Ser¹⁶ N151 C4:C12, Gln¹-Asp²-Asp³-Cys⁴-Glu⁵-Glu⁶-Cys⁷-Ile⁸-Asn⁹-Met¹⁰-Ala¹¹-Cys¹²-Thr¹³- 232 C7:C15 Gly¹⁴-Cys¹⁵-Ser¹⁶ N152 C4:C12, Gln¹-Glu²-Asp³-Cys⁴-Glu⁵-Glu⁶-Cys⁷-Ile⁸-Asn⁹-Met¹⁰-Ala¹¹-Cys¹²-Thr¹³- 233 C7:C15 Gly¹⁴-Cys¹⁵-Ser¹⁶ N153 C4:C12, Gln¹-Glu²-Glu³-Cys⁴-Glu⁵-Tyr⁶-Cys⁷-Ile⁸-Asn⁹-Met¹⁰-Ala¹¹-Cys¹²-Thr¹³- 234 C7:C15 Gly¹⁴-Cys¹⁵-Ser¹⁶ N154 C4:C12, Gln¹-Asp²-Glu³-Cys⁴-Glu⁵-Tyr⁶-Cys⁷-Ile⁸-Asn⁹-Met¹⁰-Ala¹¹-Cys¹²-Thr¹³- 235 C7:C15 Gly¹⁴-Cys¹⁵-Ser¹⁶ N155 C4:C12, Gln¹-Asp²-Asp³-Cys⁴-Glu⁵-Tyr⁶-Cys⁷-Ile⁸-Asn⁹-Met¹⁰-Ala¹¹-Cys¹²-Thr¹³- 236 C7:C15 Gly¹⁴-Cys¹⁵-Ser¹⁶ N156 C4:C12, Gln¹-Glu²-Asp³-Cys⁴-Glu⁵-Tyr⁶-Cys⁷-Ile⁸-Asn⁹-Met¹⁰-Ala¹¹-Cys¹²-Thr¹³- 237 C7:C15 Gly¹⁴-Cys¹⁵-Ser¹⁶ N157 C4:C12, Gln¹-Glu²-Glu³-Cys⁴-Glu⁵-Ile⁶-Cys⁷-Ile⁸-Asn⁹-Met¹⁰-Ala¹¹-Cys¹²-Thr¹³- 238 C7:C15 Gly¹⁴-Cys¹⁵-Ser¹⁶ N158 C4:C12, Gln¹-Asp²-Glu³-Cys⁴-Glu⁵-Ile⁶-Cys⁷-Ile⁸-Asn⁹-Met¹⁰-Ala¹¹-Cys¹²-Thr¹³- 239 C7:C15 Gly¹⁴-Cys¹⁵-Ser¹⁶ N159 C4:C12, Gln¹-Asp²-Asp³-Cys⁴-Glu⁵-Ile⁶-Cys⁷-Ile⁸-Asn⁹-Met¹⁰-Ala¹¹-Cys¹²-Thr¹³- 240 C7:C15 Gly¹⁴-Cys¹⁵-Ser¹⁶ N160 C4:C12, Gln¹-Glu²-Asp³-Cys⁴-Glu⁵-Ile⁶-Cys⁷-Ile⁸-Asn⁹-Met¹⁰-Ala¹¹-Cys¹²-Thr¹³- 241 C7:C15 Gly¹⁴-Cys¹⁵-Ser¹⁶

TABLE VII ST Peptide and Analogues SEQ Position of ID Name Disulfide bonds Structure NO ST C3:C8, C4:C12, Asn¹-Ser²-Ser³-Asn⁴-Ser⁵-Ser⁶-Asn⁷-Tyr⁸-Cys⁹-Cys¹⁰-Glu¹¹-Lys¹²-Cys¹³-Cys¹⁴- 242 Peptide C7:15 Asn¹⁵-Pro¹⁶-Ala¹⁷-Cys¹⁸-Thr¹⁹-G1y²⁰-Cys²¹-Tyr²² N161 C3:C8, C4:C12, PEG3-Asn¹-Phe²-Cys³-Cys⁴-Glu⁵-Thr⁶-Cys⁷-Cys⁸-Asn⁹-Pro¹⁰-Ala¹¹-Cys¹²-Thr¹³- 243 C7:15 Gly¹⁴-Cys¹⁵-Tyr¹⁶-PEG3 N162 C3:C8, C4:C12, PEG3-Asn¹-Phe²-Cys³-Cys⁴-Glu⁵-Thr⁶-Cys⁷-Cys⁸-Asn⁹-Pro¹⁰-Ala¹¹-Cys¹²-Thr¹³- 244 C7:15 Gly¹⁴-Cys¹⁵-Tyr¹⁶ N163 C3:C8, C4:C12, Asn¹-Phe²-Cys³-Cys⁴-Glu⁵-Thr⁶-Cys⁷-Cys⁸-Asn⁹-Pro¹⁰-Ala¹¹-Cys¹²-Thr¹³-Gly¹⁴- 245 C7:15 Cys¹⁵-Tyr¹⁶-PEG3 N164 C3:C8, C4:C12, Asn¹-Phe²-Cys³-Cys⁴-Glu⁵-Tyr⁶-Cys⁷-Cys⁸-Asn⁹-Pro¹⁰-Ala¹¹-Cys¹²-Thr¹³-Gly¹⁴- 246 C7:15 Cys¹⁵-Tyr¹⁶ N165 C3:C8, C4:C12, dAsn¹-Phe²-Cys³-Cys⁴-Glu⁵-Tyr⁶-Cys⁷-Cys⁸-Asn⁹-Pro¹⁰-Ala¹¹-Cys¹²-Thr¹³- 247 C7:15 Gly¹⁴-Cys¹⁵-dTyr¹⁶ N166 C3:C8, C4:C12, Asn¹-Phe²-Cys³-Cys⁴-Glu⁵-Tyr⁶-Cys⁷-Cys⁸-Asn⁹-Pro¹⁰-Ala¹¹-Cys¹²-Thr¹³-Gly¹⁴- 248 C7:15 Cys¹⁵-dTyr¹⁶ N167 C3:C8, C4:C12, dAsn¹-Phe²-Cys³-Cys⁴-Glu⁵-Tyr⁶-Cys⁷-Cys⁸-Asn⁹-Pro¹⁰-Ala¹¹-Cys¹²-Thr¹³- 249 C7:15 Gly¹⁴-Cys¹⁵-Tyr¹⁶

1.3 Methods of Use

The invention provides methods for treating or preventing gastrointestinal disorders and increasing gastrointestinal motility in a subject in need thereof by administering an effective amount of a GCC agonist formulation to the subject. Non-limiting examples of gastrointestinal disorders that can be treated or prevented according to the methods of the invention include irritable bowel syndrome (IBS), non-ulcer dyspepsia, chronic intestinal pseudo-obstruction, functional dyspepsia, colonic pseudo-obstruction, duodenogastric reflux, gastroesophageal reflux disease (GERD), ileus (e.g., post-operative ileus), gastroparesis, heartburn (high acidity in the GI tract), constipation (e.g., constipation associated with use of medications such as opioids, osteoarthritis drugs, or osteoporosis drugs); post surgical constipation, constipation associated with neuropathic disorders, Crohn's disease, and ulcerative colitis.

The invention also provides methods for treating gastrointestinal cancer in a subject in need thereof by administering an effective amount of a GCC agonist formulation to the subject. Non-limiting examples of gastrointestinal cancers that can be treated according to the methods of the invention include gastric cancer, esophageal cancer, pancreatic cancer, colorectal cancer, intestinal cancer, anal cancer, liver cancer, gallbladder cancer, or colon cancer.

Disorders are treated, prevented or alleviated by administering to a subject, e.g., a mammal such as a human in need thereof, a therapeutically effective dose of a GCC agonist peptide. The GCC agonist peptides may be in a pharmaceutical composition in unit dose form, together with one or more pharmaceutically acceptable excipients. The term “unit dose form” refers to a single drug delivery entity, e.g., a tablet, capsule, solution or inhalation formulation. The amount of peptide present should be sufficient to have a positive therapeutic effect when administered to a patient (typically, between 10 μg and 3 g). What constitutes a “positive therapeutic effect” will depend upon the particular condition being treated and will include any significant improvement in a condition readily recognized by one of skill in the art.

The GCC agonist formulations of the invention are particularly useful in the treatment or prevention of diseases and disorders that benefit from selective targeting of the GCC agonist to a region of the gastrointestinal tract. In one embodiment, the GCC agonist formulation targets delivery of the GCC agonist to the duodenum or jejunum. In accordance with this embodiment, the GCC agonist formulation is particularly useful for the treatment or prevention of one or more of the following: irritable bowel syndrome (preferably constipation predominant), non-ulcer dyspepsia, chronic intestinal pseudo-obstruction, functional dyspepsia, colonic pseudo-obstruction, duodenogastric reflux, gastro esophageal reflux disease, chronic idiopathic constipation, gastroparesis, heartburn, gastric cancer, and H. pylori infection. In one embodiment, the GCC agonist formulation for targeted delivery to the duodenum or jejunum comprises a pH dependent polymer with a threshold pH between 4.5 and 6. In another embodiment, the GCC agonist formulation targets delivery of the GCC agonist to the ileum or colon. In accordance with this embodiment, the GCC agonist formulation is particularly useful for the treatment or prevention of one or more of the following: ileitis (post-operative ileitis), Crohn's disease, ulcerative colitis, terminal ileitis, and colon cancer. In one embodiment, the GCC agonist formulation for targeted delivery to the ileum or colon comprises a pH dependent polymer with a threshold pH between 6.5 and 7.5.

The specific dose of the GCC agonist to be administered in the formulations of the invention will depend on the nature of the disease or disorder to be treated or prevented as well as its severity. Other factors routinely used in determining the dosage for a particular subject include the subject's body weight, general health, diet, and natural history of disease. The route of administration and scheduling of administration will also be considered. In certain embodiments, an effective dosage of a GCC agonist will typically be between about 10 μg and about 3 mg per kilogram body weight, preferably between about 10 μg and about 1 mg of the compound per kilogram body weight. In other embodiments, the dosage of a GCC agonist will be effective to induce anti-inflammatory activity in the target tissue, especially the large intestines (e.g., the terminal ileum and colon). In accordance with this embodiment, the effective dosage of the GCC agonist will be from 0.01 mg to 10 mg per kilogram body weight. In a preferred embodiment, the effective dosage is 0.01 mg/kg, 0.1 mg/kg, 1 mg/kg, 5 mg/kg, or 10 mg/kg body weight. Adjustments in dosage will be made using methods that are routine in the art and will be based upon the particular composition being used and clinical considerations.

The GCC agonists for use in the methods described above are preferably administered orally. Dosage forms include solutions, suspensions, emulsions, tablets, and capsules.

The total daily dose can be administered to the patient in a single dose, or in multiple subdoses. Typically, subdoses can be administered two to six times per day, preferably two to four times per day, and even more preferably two to three times per day.

The GCC agonists may be administered as either the sole active agent or in combination with one or more additional active agents. In all cases, additional active agents should be administered at a dosage that is therapeutically effective using the existing art as a guide. The GCC agonists may be administered in a single composition or sequentially with the one or more additional active agents. In one embodiment, the GCC agonist is administered in combination with one or more inhibitors of cGMP dependent phosphodiesterase such as suldinac sulfone, zaprinast, motapizone, vardenafil, or sildenifil. In another embodiment, the GCC agonist is administered in combination with one or more chemotherapeutic agents. In another embodiment, the GCC agonist is administered in combination with one or more or anti-inflammatory drugs such as steroids or non-steroidal anti-inflammatory drugs (NSAIDS), such as aspirin.

Combination therapy can be achieved by administering two or more agents, e.g., a GCC agonist peptide described herein and another compound, each of which is formulated and administered separately, or by administering two or more agents in a single formulation. Other combinations are also encompassed by combination therapy. For example, two agents can be formulated together and administered in conjunction with a separate formulation containing a third agent. While the two or more agents in the combination therapy can be administered simultaneously, they need not be. For example, administration of a first agent (or combination of agents) can precede administration of a second agent (or combination of agents) by minutes, hours, days, or weeks. Thus, the two or more agents can be administered within minutes of each other or within 1, 2, 3, 6, 9, 12, 15, 18, or 24 hours of each other or within 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 14 days of each other or within 2, 3, 4, 5, 6, 7, 8, 9, or 10 weeks of each other. In some cases even longer intervals are possible. While in many cases it is desirable that the two or more agents used in a combination therapy be present in within the patient's body at the same time, this need not be so.

The GCC agonist peptides described herein may be combined with phosphodiesterase inhibitors, e.g., sulindae sulfone, Zaprinast, sildenafil, vardenafil or tadalafil to further enhance levels of cGMP in the target tissues or organs.

Combination therapy can also include two or more administrations of one or more of the agents used in the combination. For example, if agent X and agent Y are used in a combination, one could administer them sequentially in any combination one or more times, e.g., in the order X-Y-X, X-X-Y, Y-X-Y, Y-Y-X, X-X-Y-Y, etc.

1.3.1 Exemplary Agents for Combination Therapy

The GCC agonist formulations of the invention may be administered alone or in combination with one or more additional therapeutic agents as part of a therapeutic regimen for the treatment or prevention of a gastrointestinal disease or disorder. In some embodiments, the GCC agonist formulation comprises one or more additional therapeutic agents. In other embodiments, the GCC agonist is formulated separately from the one or more additional therapeutic agents. In accordance with this embodiment, the GCC agonist is administered either simultaneously, sequentially, or at a different time than the one or more additional therapeutic agents. In one embodiment, the GCC agonist formulation is administered in combination with one or more additional therapeutic agents selected from the group consisting of phosphodiesterase inhibitors, cyclic nucleotides (such as cGMP and cAMP), a laxative (such as SENNA or METAMUCIL), a stool softner, an anti-tumor necrosis factor alpha therapy for IBD (such as REMICADE, ENBREL, or HUMIRA), and anti-inflammatory drugs (such as COX-2 inhibitors, sulfasalazine, 5-ASA derivatives and NSAIDS). In certain embodiments, the GCC agonist formulation is administered in combination with an effective dose of an inhibitor of cGMP-specific phosphodiesterase (cGMP-PDE) either concurrently or sequentially with said GCC agonist. cGMP-PDE inhibitors include, for example, suldinac sulfone, zaprinast, motapizone, vardenifil, and sildenafil. In another embodiment, the GCC agonist formulation is administered in combination with inhibitors of cyclic nucleotide transporters. Further examples of therapeutic agents that may be administered in combination with the GCC agonist formulations of the invention are given in the following sections.

1.3.1.1 Agents to Treat Gastrointestinal Cancers

The GCC agonist formulations described herein can be used in combination with one or more antitumor agents including but not limited to alkylating agents, epipodophyllotoxins, nitrosoureas, antimetabolites, vinca alkaloids, anthracycline antibiotics, nitrogen mustard agents, and the like. Particular antitumor agents include tamoxifen, taxol, etoposide, and 5-fluorouracil. In one embodiment, the GCC agonist formulations are used in combination with an antiviral agent or a monoclonal antibody.

Non-limiting examples of antitumor agents that can be used in combination with the GCC agonist formulations of the invention for the treatment of colon cancer include anti-proliferative agents, agents for DNA modification or repair, DNA synthesis inhibitors, DNA/RNA transcription regulators, RNA processing inhibitors, agents that affect protein expression, synthesis and stability, agents that affect protein localization or their ability to exert their physiological action, agents that interfere with protein-protein or protein-nucleic acid interactions, agents that act by RNA interference, receptor binding molecules of any chemical nature (including small molecules and antibodies), targeted toxins, enzyme activators, enzyme inhibitors, gene regulators, HSP-90 inhibitors, molecules interfering with microtubules or other cytoskeletal components or cell adhesion and motility, agents for phototherapy, and therapy adjuncts.

Representative anti-proliferative agents include N-acetyl-D-sphingosine (C.sub.2 ceramide), apigenin, berberine chloride, dichloromethylenediphosphonic acid disodium salt, loe-emodine, emodin, HA 14-1, N-hexanoyl-D-sphingosine (C.sub.6 ceramide), 7b-hydroxycholesterol, 25-hydroxycholesterol, hyperforin, parthenolide, and rapamycin.

Representative agents for DNA modification and repair include aphidicolin, bleomycin sulfate, carboplatin, carmustine, chlorambucil, cyclophosphamide monohydrate, cyclophosphamide monohydrate ISOPAC®, cis-diammineplatinum(II) dichloride (Cisplatin), esculetin, melphalan, methoxyamine hydrochloride, mitomycin C, mitoxantrone dihydrochloride, oxaliplatin, and streptozocin.

Representative DNA synthesis inhibitors include (.+−.)amethopterin (methotrexate), 3-amino-1,2,4-benzotriazine 1,4-dioxide, aminopterin, cytosine b-D-arabinofuranoside (Ara-C), cytosine b-D-arabinofuranoside (Ara-C) hydrochloride, 2-fluoroadenine-9-b-D-arabinofuranoside (Fludarabine des-phosphate; F-ara-A), 5-fluoro-5′-deoxyuridinc, 5-fluorouracil, ganciclovir, hydroxyurea, 6-mercaptopurine, and 6-thioguanine.

Representative DNA/RNA transcription regulators include actinomycin D, daunorubicin hydrochloride, 5,6-dichlorobenzimidazole 1-b-D-ribofuranoside, doxorubicin hydrochloride, homoharringtonine, and idarubicin hydrochloride.

Representative enzyme activators and inhibitors include forskolin, DL-aminoglutethimide, apicidin, Bowman-Birk Inhibitor, butein, (S)-(+)-camptothecin, curcumin, (−)-deguelin, (−)-depudecin, doxycycline hyclate, etoposide, formestane, fostriecin sodium salt, hispidin, 2-imino-1-imidazolidineacetic acid (Cyclocreatine), oxamflatin, 4-phenylbutyric acid, roscovitine, sodium valproate, trichostatin A, tyrphostin AG 34, tyrphostin AG 879, urinary trypsin inhibitor fragment, valproic acid (2-propylpentanoic acid), and XK469.

Representative gene regulators include 5-aza-2′-deoxycytidine, 5-azacytidine, cholecalciferol (Vitamin D3), ciglitizone, cyproterone acetate, 15-deoxy-D.sup.12,14-prostaglandin J.sub.2, epitestosterone, flutamide, glycyrrhizic acid ammonium salt (glycyrrhizin), 4-hydroxytamoxifen, mifepristone, procainamide hydrochloride, raloxifene hydrochloride, all trans-retinal (vitamin A aldehyde), retinoic acid (vitamin A acid), 9-cis-retinoic acid, 13-cis-retinoic acid, retinoic acid p-hydroxyanilide, retinol (Vitamin A), tamoxifen, tamoxifen citrate salt, tetradecylthioacetic acid, and troglitazone.

Representative HSP-90 inhibitors include 17-(allylamino)-17-demethoxygeldanamycin and geldanamycin.

Representative microtubule inhibitors include colchicines, dolastatin 15, nocodazole, taxanes and in particular paclitaxel, podophyllotoxin, rhizoxin, vinblastine sulfate salt, vincristine sulfate salt, and vindesine sulfate salt and vinorelbine (Navelbine) ditartrate salt.

Representative agents for performing phototherapy include photoactive porphyrin rings, hypericin, 5-methoxypsoralen, 8-methoxypsoralen, psoralen and ursodeoxycholic acid.

Representative agents used as therapy adjuncts include amifostine, 4-amino-1,8-naphthalimide, brefeldin A, cimetidine, phosphomycin disodium salt, leuprolide (leuprorelin) acetate salt, luteinizing hormone-releasing hormone (LH-RH) acetate salt, lectin, papaverine hydrochloride, pifithrin-a, (−)-scopolamine hydrobromide, and thapsigargin.

The agents can also be anti-VEGF (vascular endothelial growth factor) agents, as such are known in the art. Several antibodies and small molecules are currently in clinical trials or have been approved that function by inhibiting VEGF, such as Avastin (Bevacizumab), SU5416, SU11248 and BAY 43-9006. The agents can also be directed against growth factor receptors such as those of the EGF/Erb-B family such as EGF Receptor (Iressa or Gefitinib, and Tarceva or Erlotinib), Erb-B2, receptor (Herceptin or Trastuzumab), other receptors (such as Rituximab or Rituxan/MabThera), tyrosine kinases, non-receptor tyrosine kinases, cellular serine/threonine kinases (including MAP kinases), and various other proteins whose deregulation contribute to oncogenesis (such as small/Ras family and large/heterotrimeric G proteins). Several antibodies and small molecules targeting those molecules are currently at various stages of development (including approved for treatment or in clinical trials).

In a preferred embodiment, the invention provides a method for treating colon cancer in a subject in need thereof by administering to the subject a GCC agonist formulation in combination with one or more antitumor agent selected from the group consisting of paclitaxel, docetaxel, tamoxifen, vinorelbine, gemcitabine, cisplatin, etoposide, topotecan, irinotecan, anastrozole, rituximab, trastuzumab, fludarabine, cyclophosphamide, gentuzumab, carboplatin, interferons, and doxorubicin. In a particular embodiment the antitumor agent is paclitaxel. In a further embodiment, the method further comprises an antitumor agent selected from the group consisting of 5-FU, doxorubicin, vinorelbine, cytoxan, and cisplatin.

1.3.1.2 Agents that Treat Crohn's Disease

In one embodiment, a GCC agonist formulation of the invention is administered as part of a combination therapy with one or more additional therapeutic agents for the treatment of Crohn's disease. Non-limiting examples of the one or more additional therapeutic agents include sulfasalazine and other mesalamine-containing drugs, generally known as 5-ASA agents, such as Asacol, Dipentum, or Pentasa, or infliximab (REMICADE). In certain embodiments, the one or more additional agents is a corticosteroid or an immunosuppressive agent such as 6-mercaptopurine or azathioprine. In another embodiment, the one or more additional agents is an antidiarrheal agent such as diphenoxylate, loperamide, or codeine.

1.3.1.3 Agents that Treat Ulcerative Colitis

In one embodiment, a GCC agonist formulation of the invention is administered as part of a combination therapy with one or more additional therapeutic agents for the treatment of ulcerative colitis. The agents that are used to treat ulcerative colitis overlap with those used to treat Chrohn's Disease. Non-limiting examples of the one or more additional therapeutic agents that can be used in combination with a GCC agonist formulation of the invention include aminosalicylates (drugs that contain 5-aminosalicyclic acid (5-ASA)) such as sulfasalazine, olsalazine, mesalamine, and balsalazide. Other therapeutic agents that can be used include corticosteroids, such as prednisone and hydrocortisone, immunomodulators, such as azathioprine, 6-mercapto-purine (6-MP), cytokines, interleukins, and lymphokines, and anti-TNF-alpha agents, including the thiazolidinediones or glitazones such as rosiglitazone and pioglitazone. In one embodiment, the one or more additional therapeutic agents includes both cyclosporine A and 6-MP or azathioprine for the treatment of active, severe ulcerative colitis.

1.3.1.4 Agents that Treat Constipation/Irritable Bowel Syndrome

In one embodiment, a GCC agonist formulation of the invention is administered as part of a combination therapy with one or more additional therapeutic agents for the treatment of constipation, such as that associated with irritable bowel syndrome. Non-limiting examples of the one or more additional therapeutic agents include laxatives such as SENNA, MIRALAX, LACTULOSE, PEG, or calcium polycarbophil), stool softeners (such as mineral oil or COLACE), bulking agents (such as METAMUCIL or bran), agents such as ZELNORM (also called tegaserod), and anticholinergic medications such as BENTYL and LEVSIN.

1.3.1.5 Agents for the Treatment of Postoperative Ileus

In one embodiment, a GCC agonist formulation of the invention is administered as part of a combination therapy with one or more additional therapeutic agents for the treatment of postoperative ileus. Non-limiting examples of the one or more additional therapeutic agents include ENTEREG (alvimopan; formerly called ado lor/ADL 8-2698), conivaptan, and related agents describes in U.S. Pat. No. 6,645,959.

1.3.1.6 Anti-Obesity Agents

In one embodiment, a GCC agonist formulation of the invention is administered as part of a combination therapy with one or more additional therapeutic agents for the treatment of obesity. Non-limiting examples of the one or more additional therapeutic agents include 1 lβ HSD-I (11-beta hydroxy steroid dehydrogenase type 1) inhibitors, such as BVT 3498, BVT 2733, 3-(1-adamantyl)-4-ethyl-5-(ethylthio)-4H-1,2,4-triazole, 3-(1-adamantyl)-5-(3,4,5-trimethoxyphenyl)-4-methyl-4H-1,2,4-triazole, 3-adamantanyl-4,5,6,7,8,9,10,11,12,3a-decahydro-1,2,4-triazolo[4,3-a][11]annulene, and those compounds disclosed in WO01/90091, WOO 1/90090, WOO 1/90092 and WO02/072084; 5HT antagonists such as those in WO03/037871, WO03/037887, and the like; 5HTIa modulators such as carbidopa, benserazide and those disclosed in U.S. Pat. No. 6,207,699, WO03/031439, and the like; 5HT2c (serotonin receptor 2c) agonists, such as BVT933, DPCA37215, IK264, PNU 22394, WAY161503, R-1065, SB 243213 (Glaxo Smith Kline) and YM 348 and those disclosed in U.S. Pat. No. 3,914,250, WO00/77010, WO02/36596, WO02/48124, WO02/10169, WO01/66548, WO02/44152, WO02/51844, WO02/40456, and WO02/40457; 5HT6 receptor modulators, such as those in WO03/030901, WO03/035061, WO03/039547, and the like; acyl-estrogens, such as oleoyl-estrone, disclosed in del Mar-Grasa, M. et al, Obesity Research, 9:202-9 (2001) and Japanese Patent Application No. JP 2000256190; anorectic bicyclic compounds such as 1426 (Aventis) and 1954 (Aventis), and the compounds disclosed in WO00/18749, WO01/32638, WO01/62746, WO01/62747, and WO03/015769; CB 1 (cannabinoid-1 receptor) antagonist/inverse agonists such as rimonabant (Acomplia; Sanofi), SR-147778 (Sanofi), SR-141716 (Sanofi), BAY 65-2520 (Bayer), and SLV 319 (Solvay), and those disclosed in patent publications U.S. Pat. No. 4,973,587, U.S. Pat. No. 5,013,837, U.S. Pat. No. 5,081,122, U.S. Pat. No. 5,112,820, U.S. Pat. No. 5,292,736, U.S. Pat. No. 5,532,237, U.S. Pat. No. 5,624,941, U.S. Pat. No. 6,028,084, U.S. Pat. No. 6,509,367, U.S. Pat. No. 6,509,367, WO96/33159, WO97/29079, WO98/31227, WO98/33765, WO98/37061, WO98/41519, WO98/43635, WO98/43636, WO99/02499, WO00/10967, WO00/10968, WO01/09120, WO01/58869, WO01/64632, WO01/64633, WO01/64634, WO01/70700, WO01/96330, WO02/076949, WO03/006007, WO03/007887, WO03/020217, WO03/026647, WO03/026648, WO03/027069, WO03/027076, WO03/027114, WO03/037332, WO03/040107, WO03/086940, WO03/084943 and EP658546; CCK-A (cholecystokinin-A) agonists, such as AR-R 15849, GI 181771 (GSK), JMV-180, A-71378, A-71623 and SR146131 (Sanofi), and those described in U.S. Pat. No. 5,739,106; CNTF (Ciliary neurotrophic factors), such as GI-181771 (Glaxo-SmithKline), SR1 46131 (Sanofi Synthelabo), butabindide, PD 170,292, and PD 149164 (Pfizer); CNTF derivatives, such as Axokine® (Regeneron), and those disclosed in WO94/09134, WO98/22128, and WO99/43813; dipeptidyl peptidase IV (DP-IV) inhibitors, such as isoleucine thiazolidide, valine pyrrolidide, NVP-DPP728, LAF237, P93/01, P 3298, TSL 225 (tryptophyl-1,2,3,4-tetrahydroisoquinoline-3-carboxylic acid; disclosed by Yamada et al, Bioorg. & Med. Chem. Lett. 8 (1998) 1537-1540), TMC-2A/2B/2C, CD26 inhibitors, FE 999011, P9310/K364, VIP 0177, SDZ 274-444, 2-cyanopyrrolidides and 4-cyanopyrrolidides as disclosed by Ashworth et al, Bioorg. & Med. Chem. Lett., Vol. 6, No. 22, pp 1163-1166 and 2745-2748 (1996) and the compounds disclosed patent publications. WO99/38501, WO99/46272, WO99/67279 (Probiodrug), WO99/67278 (Probiodrug), WO99/61431 (Probiodrug), WO02/083128, WO02/062764, WO03/000180, WO03/000181, WO03/000250, WO03/002530, WO03/002531, WO03/002553, WO03/002593, WO03/004498, WO03/004496, WO03/017936, WO03/024942, WO03/024965, WO03/033524, WO03/037327 and EP1258476; growth hormone secretagogue receptor agonists/antagonists, such as NN703, hexarelin, MK-0677 (Merck), SM-130686, CP-424391 (Pfizer), LY 444,711 (Eli Lilly), L-692,429 and L-163,255, and such as those disclosed in U.S. Ser. No. 09/662,448, U.S. provisional application 60/203,335, U.S. Pat. No. 6,358,951, US2002049196, US2002/022637, WO01/56592 and WO02/32888; H3 (histamine H3) antagonist/inverse agonists, such as thioperamide, 3-(1H-imidazol-4-yl)propyl N-(4-pentenyl)carbamate), clobenpropit, iodophenpropit, imoproxifan, GT2394 (Gliatech), and A331440, O-[3-(1H-imidazol-4-yl)propanol]carbamates (Kiec-Kononowicz, K. et al., Pharmazie, 55:349-55 (2000)), piperidine-containing histamine H3-receptor antagonists (Lazewska, D. et al., Pharmazie, 56:927-32 (2001), benzophenone derivatives and related compounds (Sasse, A. et al., Arch. Pharm. (Weinheim) 334:45-52 (2001)), substituted N-phenylcarbamates (Reidemeister, S. et al., Pharmazie, 55:83-6 (2000)), and proxifan derivatives (Sasse, A. et al., J. Med. Chem. 43:3335-43 (2000)) and histamine H3 receptor modulators such as those disclosed in WO02/15905, WO03/024928 and WO03/024929; leptin derivatives, such as those disclosed in U.S. Pat. No. 5,552,524, U.S. Pat. No. 5,552,523, U.S. Pat. No. 5,552,522, U.S. Pat. No. 5,521,283, WO96/23513, WO96/23514, WO96/23515, WO96/23516, WO96/23517, WO96/23518, WO96/23519, and WO96/23520; leptin, including recombinant human leptin (PEG-OB, Hoffman La Roche) and recombinant methionyl human leptin (Amgen); lipase inhibitors, such as tetrahydrolipstatin (orlistat/Xenical®), Triton WR1 339, RHC80267, lipstatin, teasaponin, diethylumbelliferyl phosphate, FL-386, WAY-121898, Bay-N-3176, valilactone, esteracin, ebelactone A, ebelactone B, and RHC 80267, and those disclosed in patent publications WO01/77094, U.S. Pat. No. 4,598,089, U.S. Pat. No. 4,452,813, U.S. Pat. No. 5,512,565, U.S. Pat. No. 5,391,571, U.S. Pat. No. 5,602,151, U.S. Pat. No. 4,405,644, U.S. Pat. No. 4,189,438, and U.S. Pat. No. 4,242,453; lipid metabolism modulators such as maslinic acid, erythrodiol, ursolic acid uvaol, betulinic acid, betulin, and the like and compounds disclosed in WO03/011267; Mc4r (melanocortin 4 receptor) agonists, such as CHIR86036 (Chiron), ME-10142, ME-10145, and HS-131 (Melacure), and those disclosed in PCT publication Nos. WO99/64002, WO00/74679, WOO 1/991752, WOO 1/25192, WOO 1/52880, WOO 1/74844, WOO 1/70708, WO01/70337, WO01/91752, WO02/059095, WO02/059107, WO02/059108, WO02/059117, WO02/06276, WO02/12166, WO02/11715, WO02/12178, WO02/15909, WO02/38544, WO02/068387, WO02/068388, WO02/067869, WO02/081430, WO03/06604, WO03/007949, WO03/009847, WO03/009850, WO03/013509, and WO03/031410; Mc5r (melanocortin 5 receptor) modulators, such as those disclosed in WO97/19952, WO00/15826, WO00/15790, US20030092041; melanin-concentrating hormone 1 receptor (MCHR) antagonists, such as T-226296 (Takeda), SB 568849, SNP-7941 (Synaptic), and those disclosed in patent publications WOO 1/21169, WO01/82925, WO01/87834, WO02/051809, WO02/06245, WO02/076929, WO02/076947, WO02/04433, WO02/51809, WO02/083134, WO02/094799, WO03/004027, WO03/13574, WO03/15769, WO03/028641, WO03/035624, WO03/033476, WO03/033480, JP13226269, and JP1437059; mGluR5 modulators such as those disclosed in WO03/029210, WO03/047581, WO03/048137, WO03/051315, WO03/051833, WO03/053922, WO03/059904, and the like; serotoninergic agents, such as fenfluramine (such as Pondimin® (Benzeneethanamine, N-ethyl-alpha-methyl-3-(trifluoromethyl)-, hydrochloride), Robbins), dexfenfluramine (such as Redux® (Benzeneethanamine, N-ethyl-alpha-methyl-3-(trifluoromethyl)-, hydrochloride), Interneuron) and sibutramine ((Meridia®, Knoll/Reductil™) including racemic mixtures, as optically pure isomers (+) and (−), and pharmaceutically acceptable salts, solvents, hydrates, clathrates and prodrugs thereof including sibutramine hydrochloride monohydrate salts thereof, and those compounds disclosed in U.S. Pat. No. 4,746,680, U.S. Pat. No. 4,806,570, and U.S. Pat. No. 5,436,272, US20020006964, WOO 1/27068, and WOO 1/62341; NE (norepinephrine) transport inhibitors, such as GW 320659, despiramine, talsupram, and nomifensine; NPY 1 antagonists, such as BIBP3226, J-115814, BIBO 3304, LY-357897, CP-671906, GI-264879A, and those disclosed in U.S. Pat. No. 6,001,836, WO96/14307, WO01/23387, WO99/51600, WO01/85690, WO01/85098, WO01/85173, and WO01/89528; NPY5 (neuropeptide Y Y5) antagonists, such as 152,804, GW-569180A, GW-594884A, GW-587081X, GW-548118X, FR235208, FR226928, FR240662, FR252384, 1229U91, GI-264879A, CGP71683A, LY-377897, LY-366377, PD-160170, SR-120562A, SR-120819A, JCF-104, and H409/22 and those compounds disclosed in patent publications U.S. Pat. No. 6,140,354, U.S. Pat. No. 6,191,160, U.S. Pat. No. 6,218,408, U.S. Pat. No. 6,258,837, U.S. Pat. No. 6,313,298, U.S. Pat. No. 6,326,375, U.S. Pat. No. 6,329,395, U.S. Pat. No. 6,335,345, U.S. Pat. No. 6,337,332, U.S. Pat. No. 6,329,395, U.S. Pat. No. 6,340,683, EP01010691, EP-01044970, WO97/19682, WO97/20820, WO97/20821, WO97/20822, WO97/20823, WO98/27063, WO00/107409, WO00/185714, WO00/185730, WO00/64880, WO00/68197, WO00/69849, WO/0113917, WO01/09120, WO01/14376, WO01/85714, WO01/85730, WO01/07409, WO01/02379, WO01/23388, WO01/23389, WOO 1/44201, WO01/62737, WO01/62738, WO01/09120, WO02/20488, WO02/22592, WO02/48152, WO02/49648, WO02/051806, WO02/094789, WO03/009845, WO03/014083, WO03/022849, WO03/028726 and Norman et al, J. Med. Chem. 43:4288-4312 (2000); opioid antagonists, such as nalmefene (REVEX®), 3-methoxynaltrexone, methylnaltrexone, naloxone, and naltrexone (e.g. PT901; Pain Therapeutics, Inc.) and those disclosed in US20050004155 and WO00/21509; orexin antagonists, such as SB-334867-A and those disclosed in patent publications WO01/96302, WO01/68609, WO02/44172, WO02/51232, WO02/51838, WO02/089800, WO02/090355, WO03/023561, WO03/032991, and WO03/037847; PDE inhibitors (e.g. compounds which slow the degradation of cyclic AMP (cAMP) and/or cyclic GMP (cGMP) by inhibition of the phosphodiesterases, which can lead to a relative increase in the intracellular concentration of cAMP and cGMP; possible PDE inhibitors are primarily those substances which are to be numbered among the class consisting of the PDE3 inhibitors, the class consisting of the PDE4 inhibitors and/or the class consisting of the PDE5 inhibitors, in particular those substances which can be designated as mixed types of PDE3/4 inhibitors or as mixed types of PDE3/4/5 inhibitors) such as those disclosed in patent publications DE1470341, DE2108438, DE2123328, DE2305339, DE2305575, DE2315801, DE2402908, DE2413935, DE2451417, DE2459090, DE2646469, DE2727481, DE2825048, DE2837161, DE2845220, DE2847621, DE2934747, DE3021792, DE3038166, DE3044568, EP000718, EP0008408, EP0010759, EP0059948, EP0075436, EP0096517, EPOl 12987, EPOl 16948, EP0150937, EP0158380, EP0161632, EP0161918, EP0167121, EP0199127, EP0220044, EP0247725, EP0258191, EP0272910, EP0272914, EP0294647, EP0300726, EP0335386, EP0357788, EP0389282, EP0406958, EP0426180, EP0428302, EP0435811, EP0470805, EP0482208, EP0490823, EP0506194, EP0511865, EP0527117, EP0626939, EP0664289, EP0671389, EP0685474, EP0685475, EP0685479, JP92234389, JP94329652, JP95010875, U.S. Pat. No. 4,963,561, U.S. Pat. No. 5,141,931, WO9117991, WO9200968, WO9212961, WO9307146, WO9315044, WO9315045, WO9318024, WO9319068, WO9319720, WO9319747, WO9319749, WO9319751, WO9325517, WO9402465, WO9406423, WO9412461, WO9420455, WO9422852, WO9425437, WO9427947, WO9500516, WO9501980, WO9503794, WO9504045, WO9504046, WO9505386, WO9508534, WO9509623, WO9509624, WO9509627, WO9509836, WO9514667, WO9514680, WO9514681, WO9517392, WO9517399, WO9519362, WO9522520, WO9524381, WO9527692, WO9528926, WO9535281, WO9535282, WO9600218, WO9601825, WO9602541, WO9611917, DE3142982, DEl 116676, DE2162096, EP0293063, EP0463756, EP0482208, EP0579496, EP0667345 U.S. Pat. No. 6,331,543, US20050004222 (including those disclosed in formulas I-XIII and paragraphs 37-39, 85-0545 and 557-577), WO9307124, EP0163965, EP0393500, EP0510562, EP0553174, WO9501338 and WO9603399, as well as PDE5 inhibitors (such as RX-RA-69, SCH-51866, KT-734, vesnarinone, zaprinast, SKF-96231, ER-21355, BF/GP-385, NM-702 and sildenafil (Viagra™)), PDE4 inhibitors (such as etazolate, ICI63197, RP73401, imazolidinone (RO-20-1724), MEM 1414 (R1533/R1500; Pharmacia Roche), denbufylline, rolipram, oxagrelate, nitraquazone, Y-590, DH-6471, SKF-94120, motapizone, lixazinone, indolidan, olprinone, atizoram, KS-506-G, dipamfylline, BMY-43351, atizoram, arofylline, filaminast, PDB-093, UCB-29646, CDP-840, SKF-107806, piclamilast, RS-17597, RS-25344-000, SB-207499, TIBENELAST, SB-210667, SB-211572, SB-211600, SB-212066, SB-212179, GW-3600, CDP-840, mopidamol, anagrelide, ibudilast, amrinone, pimobendan, cilostazol, quazinone and N-(3,5-dichloropyrid-4-yl)-3-cyclopropylmethoxy4-difluoromethoxybenzamide, PDE3 inhibitors (such as ICI153, 100, bemorandane (RWJ 22867), MCI-154, UD-CG 212, sulmazole, ampizone, cilostamide, carbazeran, piroximone, imazodan, CI-930, siguazodan, adibendan, saterinone, SKF-95654, SDZ-MKS-492, 349-U-85, emoradan, EMD-53998, EMD-57033, NSP-306, NSP-307, revizinone, NM-702, WIN-62582 and WIN-63291, enoximone and milrinone, PDE3/4 inhibitors (such as benafentrine, trequinsin, ORG-30029, zardaverine, L-686398, SDZ-ISQ-844, ORG-20241, EMD-54622, and tolafentrine) and other PDE inhibitors (such as vinpocetin, papaverine, enprofylline, cilomilast, fenoximone, pentoxifylline, roflumilast, tadalafil (Cialis®), theophylline, and vardenafil (Levitra®); Neuropeptide Y2 (NPY2) agonists include but are not limited to: polypeptide YY and fragments and variants thereof (e.g. YY3-36 (PYY3-36) (N. Engl. J. Med. 349:941, 2003; IKPEAPGE DASPEELNRY YASLRHYLNL VTRQRY (SEQ ID NO:XXX)) and PYY agonists such as those disclosed in WO02/47712, WO03/026591, WO03/057235, and WO03/027637; serotonin reuptake inhibitors, such as, paroxetine, fluoxetine (Prozac™), fluvoxamine, sertraline, citalopram, and imipramine, and those disclosed in U.S. Pat. No. 6,162,805, U.S. Pat. No. 6,365,633, WO03/00663, WOO 1/27060, and WOO 1/162341; thyroid hormone β agonists, such as KB-2611 (KaroBioBMS), and those disclosed in WO02/15845, WO97/21993, WO99/00353, GB98/284425, U.S. Provisional Application No. 60/183,223, and Japanese Patent Application No. JP 2000256190; UCP-I (uncoupling protein-1), 2, or 3 activators, such as phytanic acid, 4-[(E)-2-(5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-2-napthalenyl)-1-propenyl]benzoic acid (TTNPB), retinoic acid, and those disclosed in WO99/00123; β3 (beta adrenergic receptor 3) agonists, such as AJ9677/TAK677 (Dainippon/Takeda), L750355 (Merck), CP331648 (Pfizer), CL-316,243, SB 418790, BRL-37344, L-796568, BMS-196085, BRL-35135A, CGP12177A, BTA-243, GW 427353, Trecadrine, Zeneca D7114, N-5984 (Nisshin Kyorin), LY-377604 (Lilly), SR 59119A, and those disclosed in U.S. Pat. No. 5,541,204, U.S. Pat. No. 5,770,615, U.S. Pat. No. 5,491,134, U.S. Pat. No. 5,776,983, U.S. Pat. No. 488,064, U.S. Pat. No. 5,705,515, U.S. Pat. No. 5,451,677, WO94/18161, WO95/29159, WO97/46556, WO98/04526 and WO98/32753, WO01/74782, WO02/32897, WO03/014113, WO03/016276, WO03/016307, WO03/024948, WO03/024953 and WO03/037881; noradrenergic agents including, but not limited to, diethylpropion (such as Tenuate® (1-propanone, 2-(diethylamino)-1-phenyl-, hydrochloride), Merrell), dextroamphetamine (also known as dextroamphetamine sulfate, dexamphetamine, dexedrine, Dexampex, Ferndex, Oxydess II, Robese, Spancap #1), mazindol ((or 5-(p-chlorophenyl)-2,5-dihydro-3H-imidazo[2,1-a]isoindol-5-ol) such as Sanorex®, Novartis or Mazanor®, Wyeth Ayerst), phenylpropanolamine (or Benzenemethanol, alpha-(1-aminoethyl)-, hydrochloride), phentermine ((or Phenol, 3-[[4,5-dihydro-1H-imidazol-2-yl)ethyl](4-methylpheny-1)amino], monohydrochloride) such as Adipex-P®, Lemmon, FASTIN®, Smith-Kline Beecham and Ionamin®, Medeva), phendimetrazine ((or (2S,3S)-3,4-Dimethyl-2phenylmorpholine L-(+)-tartrate (1:1)) such as Metra® (Forest), Plegine® (Wyeth-Ayerst), Prelu-2® (Boehringer Ingelheim), and Statobex® (Lemmon), phendamine tartrate (such as Thephorin® (2,3,4,9-Tetrahydro-2-methyl-9-phenyl-1H-indenol[2,1-c]pyridine L-(+)-tartrate (1:1)), Hoffmann-LaRoche), methamphetamine (such as Desoxyn®, Abbot ((S)—N, (alpha)-dimethylbenzeneethanamine hydrochloride)), and phendimetrazine tartrate (such as Bontril® Slow-Release Capsules, Amarin (-3,4-Dimethyl-2-phenylmorpholine Tartrate); fatty acid oxidation upregulator/inducers such as Famoxin® (Genset); monamine oxidase inhibitors including but not limited to befloxatone, moclobemide, brofaromine, phenoxathine, esuprone, befol, toloxatone, pirlindol, amiflamine, sercloremine, bazinaprine, lazabemide, milacemide, caroxazone and other certain compounds as disclosed by WO01/12176; and other anti-obesity agents such as 5HT-2 agonists, ACC (acetyl-CoA carboxylase) inhibitors such as those described in WO03/072197, alpha-lipoic acid (alpha-LA), AOD9604, appetite suppressants such as those in WO03/40107, ATL-962 (Alizyme PLC), benzocaine, benzphetamine hydrochloride (Didrex), bladderwrack (focus vesiculosus), BRS3 (bombesin receptor subtype 3) agonists, bupropion, caffeine, CCK agonists, chitosan, chromium, conjugated linoleic acid, corticotropin-releasing hormone agonists, dehydroepiandrosterone, DGAT1 (diacylglycerol acyltransferase 1) inhibitors, DGAT2 (diacylglycerol acyltransferase 2) inhibitors, dicarboxylate transporter inhibitors, ephedra, exendin-4 (an inhibitor of glp-1) FAS (fatty acid synthase) inhibitors (such as Cerulenin and C75), fat resorption inhibitors (such as those in WO03/053451, and the like), fatty acid transporter inhibitors, natural water soluble fibers (such as psyllium, plantago, guar, oat, pectin), galanin antagonists, galega (Goat's Rue, French Lilac), garcinia cambogia, germander (teucrium chamaedrys), ghrelin antibodies and ghrelin antagonists (such as those disclosed in WO01/87335, and WO02/08250), polypeptide hormones and variants thereof which affect the islet cell secretion, such as the hormones of the secretin/gastric inhibitory polypeptide (GIP)/vasoactive intestinal polypeptide (VIP)/pituitary adenylate cyclase activating polypeptide (PACAP)/glucagon-like polypeptide II (GLP-II)/glicentin/glucagon gene family and/or those of the adrenomedullin/amylin/calcitonin gene related polypeptide (CGRP) gene family including GLP-1 (glucagon-like polypeptide 1) agonists (e.g. (1) exendin-4, (2) those GLP-I molecules described in US20050130891 including GLP-1(7-34), GLP-1(7-35), GLP-1(7-36) or GLP-1(7-37) in its C-terminally carboxylated or amidated form or as modified GLP-I polypeptides and modifications thereof including those described in paragraphs 17-44 of US20050130891, and derivatives derived from GLP-1-(7-34)COOH and the corresponding acid amide are employed which have the following general formula: R—NH-HAEGTFTSDVSYLEGQAAKEFIAWLVK-CONH₂ wherein R=H or an organic compound having from 1 to 10 carbon atoms. Preferably, R is the residue of a carboxylic acid. Particularly preferred are the following carboxylic acid residues: formyl, acetyl, propionyl, isopropionyl, methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, tert-butyl.) and glp-1 (glucagon-like polypeptide-1), glucocorticoid antagonists, glucose transporter inhibitors, growth hormone secretagogues (such as those disclosed and specifically described in U.S. Pat. No. 5,536,716), interleukin-6 (IL-6) and modulators thereof (as in WO03/057237, and the like), L-carnitine, Mc3r (melanocortin 3 receptor) agonists, MCH2R (melanin concentrating hormone 2R) agonist/antagonists, melanin concentrating hormone antagonists, melanocortin agonists (such as Melanotan II or those described in WO 99/64002 and WO 00/74679), nomame herba, phosphate transporter inhibitors, phytopharm compound 57 (CP 644,673), pyruvate, SCD-I (stearoyl-CoA desaturase-1) inhibitors, T71 (Tularik, Inc., Boulder Colo.), Topiramate (Topimax®, indicated as an anti-convulsant which has been shown to increase weight loss), transcription factor modulators (such as those disclosed in WO03/026576), β-hydroxy steroid dehydrogenase-1 inhibitors (β-HSD-I), β-hydroxy-β-methylbutyrate, p57 (Pfizer), Zonisamide (Zonegran™, indicated as an anti-epileptic which has been shown to lead to weight loss), and the agents disclosed in US20030119428 paragraphs 20-26.

1.3.1.7 Phosphodiesterase Inhibitors

In certain embodiments, the regimen of combination therapy includes the administration of one or more phosphodiesterase (“PDE”) inhibitors. PDE inhibitors slow the degradation of cyclic AMP (cAMP) and/or cyclic GMP (cGMP) by inhibiting phosphodiesterases, which can lead to a relative increase in the intracellular concentration of cAMP and/or cGMP. Non-limiting examples of PDE inhibitors that can be used in combination with the GCC agonists of the invention include PDE3 inhibitors, PDE4 inhibitors and/or PDE5 inhibitors, in particular those substances which can be designated as mixed types of PDE3/4 inhibitors or as mixed types of PDE3/4/5 inhibitors. Non-limiting examples of such PDE inhibitors are described in the following patent applications and patents: DE1470341, DE2108438, DE2123328, DE2305339, DE2305575, DE2315801, DE2402908, DE2413935, DE2451417, DE2459090, DE2646469, DE2727481, DE2825048, DE2837161, DE2845220, DE2847621, DE2934747, DE3021792, DE3038166, DE3044568, EP000718, EP0008408, EP0010759, EP0059948, EP0075436, EP0096517, EPOl 12987, EPOl 16948, EP0150937, EP0158380, EP0161632, EP0161918, EP0167121, EP0199127, EP0220044, EP0247725, EP0258191, EP0272910, EP0272914, EP0294647, EP0300726, EP0335386, EP0357788, EP0389282, EP0406958, EP0426180, EP0428302, EP0435811, EP0470805, EP0482208, EP0490823, EP0506194, EP0511865, EP0527117, EP0626939, EP0664289, EP0671389, EP0685474, EP0685475, EP0685479, JP92234389, JP94329652, JP95010875, U.S. Pat. Nos. 4,963,561, 5,141,931, WO9117991, WO9200968, WO9212961, WO9307146, WO9315044, WO9315045, WO9318024, WO9319068, WO9319720, WO9319747, WO9319749, WO9319751, WO9325517, WO9402465, WO9406423, WO9412461, WO9420455, WO9422852, WO9425437, WO9427947, WO9500516, WO9501980, WO9503794, WO9504045, WO9504046, WO9505386, WO9508534, WO9509623, WO9509624, WO9509627, WO9509836, WO9514667, WO9514680, WO9514681, WO9517392, WO9517399, WO9519362, WO9522520, WO9524381, WO9527692, WO9528926, WO9535281, WO9535282, WO9600218, WO9601825, WO9602541, WO9611917, DE3142982, DEl 116676, DE2162096, EP0293063, EP0463756, EP0482208, EP0579496, EP0667345 U.S. Pat. No. 6,331,543, US20050004222 (including those disclosed in formulas I-XIII and paragraphs 37-39, 85-0545 and 557-577) and WO9307124, EP0163965, EP0393500, EP0510562, EP0553174, WO9501338 and WO9603399. PDE5 inhibitors which may be mentioned by way of example are RX-RA-69, SCH-51866, KT-734, vesnarinone, zaprinast, SKF-96231, ER-21355, BF/GP-385, NM-702 and sildenafil (Viagra®). PDE4 inhibitors which may be mentioned by way of example are RO-20-1724, MEM 1414 (R1533/R1500; Pharmacia Roche), DENBUFYLLINE, ROLIPRAM, OXAGRELATE, NITRAQUAZONE, Y-590, DH-6471, SKF-94120, MOTAPIZONE, LIXAZINONE, INDOLIDAN, OLPRINONE, ATIZORAM, KS-506-G, DIPAMFYLLINE, BMY-43351, ATIZORAM, AROFYLLINE, FILAMINAST, PDB-093, UCB-29646, CDP-840, SKF-107806, PICLAMILAST, RS-17597, RS-25344-000, SB-207499, TIBENELAST, SB-210667, SB-211572, SB-211600, SB-212066, SB-212179, GW-3600, CDP-840, MOPIDAMOL, ANAGRELIDE, IBUDILAST, AMRINONE, PIMOBENDAN, CILOSTAZOL, QUAZINONE and N-(3,5-dichloropyrid-4-yl)-3-cyclopropylmethoxy4-difluoromethoxybenzamide. PDE3 inhibitors which may be mentioned by way of example are SULMAZOLE, AMPIZONE, CILOSTAMIDE, CARBAZERAN, PIROXIMONE, IMAZODAN, CI-930, SIGUAZODAN, ADIBENDAN, SATERINONE, SKF-95654, SDZ-MKS-492, 349-U-85, EMORADAN, EMD-53998, EMD-57033, NSP-306, NSP-307, REVIZINONE, NM-702, WIN-62582 and WIN-63291, ENOXIMONE and MILRINONE. PDE3/4 inhibitors which may be mentioned by way of example are BENAFENTRINE, TREQUINSIN, ORG-30029, ZARDAVERINE, L-686398, SDZ-ISQ-844, ORG-20241, EMD-54622, and TOLAFENTRINE. Other PDE inhibitors include: cilomilast, pentoxifylline, roflumilast, tadalafil (Cialis®), theophylline, and vardenafil (Levitra®), zaprinast (PDE5 specific). GCC AGONIST

1.3.1.8 Analgesic Agents

In certain embodiments, the regimen of combination therapy includes the administration of one or more analgesic agents, e.g., an analgesic compound or an analgesic polypeptide. In some embodiments, the GCC agonist formulation is administered simultaneously or sequentially with one or more analgesic agents. In other embodiments, the GCC agonist is covalently linked or attached to an analgesic agent to create a therapeutic conjugate. Non-limiting examples of analgesic agents that can be used include calcium channel blockers, 5HT receptor antagonists (for example 5HT3, 5HT4 and 5HT1 receptor antagonists), opioid receptor agonists (loperamide, fedotozine, and fentanyl), NK1 receptor antagonists, CCK receptor agonists (e.g., loxiglumide), NK1 receptor antagonists, NK3 receptor antagonists, norepinephrine-serotonin reuptake inhibitors (NSRI), vanilloid and cannabanoid receptor agonists, and sialorphin. Further examples of analgesic agents in the various classes are known in the art.

In one embodiment, the analgesic agent is an analgesic polypeptide selected from the group consisting of sialorphin-related polypeptides, including those comprising the amino acid sequence QHNPR (SEQ ID NO: 239), including: VQHNPR (SEQ ID NO: 240); VRQHNPR (SEQ ID NO: 241); VRGQHNPR (SEQ ID NO: 242); VRGPQHNPR (SEQ ID NO: 243); VRGPRQHNPR (SEQ ID NO: 244); VRGPRRQHNPR (SEQ ID NO: 245); and RQHNPR (SEQ ID NO: 246). Sialorphin-related polypeptides bind to neprilysin and inhibit neprilysin-mediated breakdown of substance P and Met-enkephalin. Thus, compounds or polypeptides that are inhibitors of neprilysin are useful analgesic agents which can be administered with the GCC agonists described herein or covalently linked to a GCC agonist to form a therapeutic conjugate. Sialorphin and related polypeptides are described in U.S. Pat. No. 6,589,750; U.S. 20030078200 A1; and WO 02/051435 A2.

In another embodiment, a GCC agonist formulation of the invention is administered as part of a regimen of combination therapy with an opioid receptor antagonist or agonist. In one embodiment, the GCC agonist and the opioid receptor antagonist or agonist are linked via a covalent bond. Non-limiting examples of opioid receptor antagonists include naloxone, naltrexone, methyl nalozone, nalmefene, cypridime, beta funaltrexamine, naloxonazine, naltrindole, nor-binaltorphimine, enkephalin pentapeptide (HOE825; Tyr-D-Lys-Gly-Phe-L-homoserine), trimebutine, vasoactive intestinal polypeptide, gastrin, glucagons. Non-limiting examples of opioid receptor agonists include fedotozine, asimadoline, and ketocyclazocine, the compounds described in WO03/097051 and WO05/007626, morphine, diphenyloxylate, frakefamide (H-Tyr-D-Ala-Phe(F)-Phe-NH 2; WO 01/019849 A1), and loperamide.

Further non-limiting examples of analgesic agents that can be used in a regimen of combination therapy along with the GCC agonist formulations of the invention include the dipeptide Tyr-Arg (kyotorphin); the chromogranin-derived polypeptide (CgA 47-66; See, e.g., Ghia et al. 2004 Regulatory polypeptides 119:199); CCK receptor agonists such as caerulein; conotoxin polypeptides; peptide analogs of thymulin (FR Application 2830451); CCK (CCKa or CCKb) receptor antagonists, including loxiglumide and dexloxiglumide (the R-isomer of loxiglumide) (WO 88/05774); 5-HT4 agonists such as tegaserod (Zelnorm®), mosapride, metoclopramide, zacopride, cisapride, renzapride, benzimidazolone derivatives such as BIMU 1 and BIMU 8, and lirexapride; calcium channel blockers such as ziconotide and related compounds described in, for example, EP625162B1, U.S. Pat. No. 5,364,842, U.S. Pat. No. 5,587,454, U.S. Pat. No. 5,824,645, U.S. Pat. No. 5,859,186, U.S. Pat. No. 5,994,305, U.S. Pat. No. 6,087,091, U.S. Pat. No. 6,136,786, WO 93/13128 A1, EP 1336409 A1, EP 835126 A1, EP 835126 B1, U.S. Pat. No. 5,795,864, U.S. Pat. No. 5,891,849, U.S. Pat. No. 6,054,429, WO 97/01351 A1; NK-I, receptor antagonists such as aprepitant (Merck & Co Inc), vofopitant, ezlopitant (Pfizer, Inc.), R-673 (Hoffmann-La Roche Ltd), SR-48968 (Sanofi Synthelabo), CP-122,721 (Pfizer, Inc.), GW679769 (Glaxo Smith Kline), TAK-637 (Takeda/Abbot), SR-14033, and related compounds described in, for example, EP 873753 A1, US 20010006972 A1, US 20030109417 A1, WO 01/52844 A1 (for a review see Giardina et al. 2003. Drugs 6:758); NK-2 receptor antagonists such as nepadutant (Menarini Ricerche SpA), saredutant (Sanoft-Synthelabo), GW597599 (Glaxo Smith Kline), SR-144190 (Sanoft-Synthelabo) and UK-290795 (Pfizer Inc); NK3 receptor antagonists such as osanetant (SR-142801; Sanoft-Synthelabo), SSR-241586, talnetant and related compounds described in, for example, WO 02/094187 A2, EP 876347 A1, WO 97/21680 A1, U.S. Pat. No. 6,277,862, WO 98/1 1090, WO 95/28418, WO 97/19927, and Boden et al. (J Med Chem. 39:1664-75, 1996); norepinephrine-serotonin reuptake inhibitors (NSRI) such as milnacipran and related compounds described in WO 03/077897; and vanilloid receptor antagonists such as arvanil and related compouds described in WO 01/64212 A1.

In addition to sialorphin-related polypeptides, analgesic polypeptides include: AspPhe, endomorphin-1, endomorphin-2, nocistatin, dalargin, lupron, ziconotide, and substance P.

EXAMPLES Example 1 Synthesis and Purification of GCC Agonist Peptides

The GCC agonist peptides were synthesized using standard methods for solid-phase peptide synthesis. Either a Boc/Bzl or Fmoc/tBu protecting group strategy was selected depending upon the scale of the peptide to be produced. In the case of smaller quantities, it is possible to get the desired product using an Fmoc/tBu protocol, but for larger quantities (1 g or more), Boc/Bzl is superior.

In each case the GCC agonist peptide was started by either using a pre-loaded Wang (Fmoc) or Merrifield (Boc) or Pam (Boc) resin. For products with C-terminal Leu, Fmoc-Leu-Wang (D-1115) or Boc-Leu-Pam resin (D-1230) or Boc-Leu-Merrifield (D-1030) Thus, for peptides containing the C-terminal d-Leu, the resin was Fmoc-dLeu-Wang Resin (D-2535) and Boc-dLeu-Merrifield, Boc-dLeu-Pam-Resin (Bachem Product D-1230 and D-1590, respectively) (SP-332 and related analogs). For peptides produced as C-terminal amides, a resin with Ramage linker (Bachem Product D-2200) (Fmoc) or mBHA (Boc) (Bachem Product D-1210 was used and loaded with the C-terminal residue as the first synthetic step.

Fmoc-tBu Overview

Each synthetic cycle consisted deprotection with 20% piperidine in DMF. Resin washes were accomplished with alternating DMF and IpOH to swell and shrink the resin, respectively. Peptide synthesis elongated the chain from the C-terminus to the N-terminus. Activation chemistry for each amino acid was with HBTU/DIEA in a 4 fold excess for 45 minutes. In automated chemistries, each amino acid was double coupled to maximize the coupling efficiency. To insure the correct position of disulfide bonds, the Cys residues were introduced as Cys (Acm) at positions 15 and 7. Cys (Trt) was positioned at Cys4 and Cys12. This protecting group strategy yields the correct topoisomer as the dominant product (75:25). (For enterotoxin analogs, a third disulfide bond protecting group (Mob) was utilized).

For peptides containing C-terminal Aeea (aminoethyloxyethyloxyacetyl) groups, these were coupled to a Ramage amide linker using the same activation chemistry above by using an Fmoc-protected Aeea derivative. The Cys numbering in these cases remains the same and the positioning of the protecting groups as well. For the peptides containing the N-terminal extension of Aeea, the Cys residue numbering will be increased by three Cys4 becomes Cys7, Cys12 becomes Cys15; Cys7 becomes Cys10 and Cys 15 becomes Cys18. The latter pair is protected with Acm and the former pair keeps the Trt groups.

For analogs containing D-amino acid substitutions, these were introduced directly by incorporating the correctly protected derivative at the desired position using the same activation chemistry described in this document. For Fmoc strategies, Fmoc-dAsn(Trt)-OH, Fmoc-dAsn(Xan)-OH, Fmoc-dAsp(tBu)-OH, Fmoc-dGlu(tBu)-OH and for Boc strategies, Boc-dAsn(Xan)-OH, Boc-dAsn(Trt)-OH, Boc-dAsp(Chx), Boc-dAsp(Bzl)-OH, Boc-dGlu(Chx)-OH and Boc-dGlu(Bzl)-OH would be utilized.

Each peptide is cleaved from the solid-phase support using a cleavage cocktail of TFA:H2O:Trisisopropylsilane (8.5:0.75:0.75) ml/g of resin for 2 hr at RT. The crude deprotected peptide is filtered to remove the spent resin beads and precipitated into ice-cold diethylether.

Each disulfide bonds was introduced orthogonally. Briefly, the crude synthetic product was dissolved in water containing NH₄OH to increase the pH to 9. Following complete solubilization of the product, the disulfide bond was made between the Trt deprotected Cys residues by titration with H₂O₂. The monocyclic product was purified by RP-HPLC. The purified mono-cyclic product was subsequently treated with a solution of iodine to simultaneously remove the Acm protecting groups and introduce the second disulfide bond.

For enterotoxin analogs, the Mob group was removed via treatment of the dicyclic product with TFA 85% containing 10% DMSO and 5% thioanisole for 2 hr at RT.

Each product was then purified by RP-HPLC using a combination buffer system of TEAP in H₂O versus MeCN, followed by TFA in H₂O versus MeCN. Highly pure fractions were combined and lyophilized. The final product was converted to an Acetate salt using either ion exchange with Acetate loaded Dow-Ex resin or using RP-HPLC using a base-wash step with NH₄OAc followed by 1% AcOH in water versus MeCN.

It is also possible to prepare enterotoxin analogs using a random oxidation methodology using Cys(Trt) in Fmoc or Cys(MeB) in Boc. Following cleavage, the disulfide bonds can be formed using disulfide interchange redox pairs such as glutathione (red/ox) and/or cysteine/cysteine. This process will yield a folded product that the disulfide pairs must be determined as there would be no way of knowing their position directly.

Boc-Bzl Process

Peptide synthesis is initiated on a Merrifield or Pam pre-loaded resin or with mBHA for peptides produced as C-terminal amides. Each synthetic cycle consists of a deprotection step with 50% TFA in MeCL2. The resin is washed repetitively with MeCl2 and MeOH. The TFA salt formed is neutralized with a base wash of 10% TEA in MeCl2. The resin is washed with MeCl2 and MeOH and lastly with DMF prior to coupling steps. A colorimetric test is conducted to ensure deprotection. Each coupling is mediated with diisopropyl carbodiimide with HOBT to form the active ester. Each coupling is allowed to continue for 2 hr at RT or overnight on difficult couplings. Recouplings are conducted with either Uronium or Phosphonium reagents until a negative colorimetric test is obtained for free primary amines. The resin is then washed with DMF, MeCl2 and MeOH and prepared for the next solid-phase step. Cys protection utilizes Cys(Acm) at positions 7 and 15, and Cys(MeB) at Cys 4 and Cys12.

Cleavage and simultaneous deprotection is accomplished by treatment with HF using anisole as a scavenger (9:1:1) ml:ml:g (resin) at 0° C. for 60 min. The peptide is subsequently extracted from the resin and precipitated in ice cold ether. The introduction of disulfide bonds and purification follows the exact same protocol described above for the Fmoc-produced product.

Example 2 In Vitro Biological and Chemical Stability of SP-304 after Incubation in Simulated Gastric Fluid (SGF)

The stability of SP-304 in the presence of simulated gastric fluid (SGF) was determined by biological activity measurements and HPLC analyses (FIGS. 1A & 1B). SP-304 (final concentration of 8.5 mg/ml) was incubated in SGF (Proteose peptone (8.3 gaiter; Difco), D-Glucose (3.5 gaiter; Sigma), NaCl (2.05 gaiter; Sigma), KH₂PO₄ (0.6 gaiter; Sigma), CaCl₂ (0.11 g/liter), KCl (0.37 g/liter; Sigma), Porcine bile (final 1× concentration 0.05 gaiter; Sigma) in PBS, Lysozyme (final 1× concentration 0.10 g/liter; Sigma) in PBS, Pepsin (final 1× concentration 0.0133 gaiter; Sigma) in PBS). SGF was made on the day of the experiment and the pH was adjusted to 2.0±0.1 using HCl or NaOH as necessary. After the pH adjustment, SGF is filter sterilized with 0.22 μm membrane filters. SP-304 (final concentration of 8.5 mg/ml) was incubated in SGF at 37° C. for 0, 15, 30, 45, 60 and 120 min, respectively, in triplicate aliquots. Following incubations, samples were snap frozen in dry ice then stored in a −80° C. freezer until assayed in duplicate.

FIG. 1A shows a bar chart showing the biological activity of SP-304 after incubation with SGF for times as indicated. The activity at 0 min was taken as 100%. The data are an average of triplicates±SD for each data point. The data demonstrate that SP-304 is resistant to breakdown in SGF for incubations lasting as long as two hours. In addition, the data also suggest that the activity of SP-304 is unaltered by exposure to the acidic pH of the SGF.

The HPLC chromatograms of samples of SP-304 incubated in SGF for 0 and 120 min are shown in FIG. 1B. Here, aliquots of the two samples were analyzed by HPLC using a previously developed method for analyzing SP-304 peptide. Samples from the SGF incubations were diluted to give a final concentration 0.17 mg/mL of SP-304. The major peak of SP-304 did not change following incubation with SGF, indicating that the peptide was resistant to SGF treatment.

Example 3 In Vitro Biological and Chemical Stability of SP-304 after Incubation in Simulated Intestinal Fluid (SIF)

The stability of SP-304 was also evaluated after incubation with simulated intestinal fluid (SIF) by measuring its biological activity and by HPLC analyses (FIGS. 2A & 2B). SIF solution was prepared by the method as described in the United States Pharmacopoeia, 24th edition, p 2236. The recipe to prepare SIF solution was as described below. The SIF solution contained NaCl (2.05 g/liter; Sigma), KH₂PO₄ (0.6 gaiter; Sigma), CaCl₂ (0.11 g/liter), KCl (0.37 gaiter; Sigma), and Pacreatin 10 mg/ml. The pH was adjusted to 6 and the solution was filter sterilized. A solution of SP-304 (8.5 mg/ml) was incubated in SGF at 37° C. for 0, 30, 60, 90, 120, 150 and 300 min respectively, in triplicate aliquots. Following incubations, samples were removed and snap frozen with dry ice and stored in a −80° C. freezer until assayed in duplicate. FIG. 2A is a bar chart showing the ability of SP-304, after incubation in SIF for times as indicated, to stimulate cGMP synthesis in T84 cells. The cGMP stimulation activity at 0 min was taken as 100%. The data are an average of 3 triplicates±SD. The data indicated that the biological activity of SP-304 is reduced by about 30% following incubation in SIF for 300 min.

The physical stability of SP-304 peptide exposed to SIF was evaluated by HPLC using the method described for SGF digestion. FIG. 2B shows HPLC chromatograms for SP-304 after incubation with heat-inactivated SIF for 300 min, and SIF for 120 min, respectively. SP-304 treated with heat-inactivated SIF remained intact (Note: the major peak of SP-304 eluting at 16.2 min), whereas SP-304 treated with SIF for 120 min was completely converted into another peak eluting at 9.4 min plus a few minor additional peaks.

FIG. 3 is a schematic representation of the possible metabolites of SP-304. The major degradation products involve Asn and Asp clipped from the N-terminus and Leu from the C-terminus of SP304. The fact that only 30% reduction in biological activity was observed even after 2 hours incubation in SIF implies that one or more of the degradation products observed in FIG. 2B are also biologically active. To address this possibility, several truncated peptides were synthesized and evaluated for their abilities to stimulate cGMP synthesis in T84 cells (FIG. 4).

FIG. 4 shows data from the analyses of various peptides in the T84 cell cGMP stimulation assay (essentially as described in Shailubhai, et al., Cancer Research 60, 5151-5157 (2000). Briefly, confluent monolayers of T-84 cells in 24-well plates were washed twice with 250 μl of DMEM containing 50 mM HEPES (pH 7.4) and pre-incubated at 37° C. for 10 minutes with 250 μl of DMEM containing 50 mM HEPES (pH 7.4) and 1 mM isobutyl methylxanthine (IBMX). Monolayers of T84 cells were then incubated with 250 μl of DMEM containing 50 mM HEPES (pH 7.4) containing one of the peptides shown in the FIG. 4 at a concentration of 1.0 μM for 30 min. After the 30 min incubation, the medium was aspirated and the reaction was terminated by the addition of 3% perchloric acid. Following centrifugation and the addition of NaOH (0.1 N) to neutralize the pH, intracellular cGMP levels were determined in lysates using a cGMP ELISA kit (Cat. No. 581021; Cayman Chemical, Ann Arbor, Mich.). Peptide incubations were run in duplicate, and samples taken from each incubation were run as duplicates in the ELISA test.

The data indicate that SP-338, the 15-mer peptide missing the leucine (L) residue at the C-terminus of SP-304, retains about 80% of the biological activity of the full length 16-mer SP-304 peptide. Thus, the C-terminal Leu clearly does make some contribution to the biological potency of the peptide. Similarly, peptides SP-327, SP-329 and SP-331, which are all missing their C-terminal Leu, also showed a 20-25% reduction in biological potency relative to their counterpart parent peptides SP-326, SP-328 and SP-330, respectively. In addition, the data also suggest that amino acid residues at the N-terminus may also contribute to the stability and/or potency of the peptides. Several additional peptides were synthesized with D-forms of amino acids replacing the corresponding L-forms at the C- and N-termini of the peptides. These peptides were evaluated for their abilities to stimulate cGMP synthesis in T84 cells as shown in FIG. 5.

The results presented in FIG. 5 indicate that substitution of L-amino acids with D-amino acids at the C- and N-termini did not significantly alter their potency relative to SP-304. Peptides SP-332, SP-333 and SP-335 all showed comparable ability to stimulate cGMP synthesis in T84 cells. These results suggest that the amino acid residues Asn, Asp and Glu at the N-terminus and Leu at the C-terminus can be replaced with their respective D-amino acid forms. On the other hand, substitution of L-leucine with D-leucine at the 6^(th) position (SP-337) resulted in virtually complete loss of biological activity.

FIG. 7 (A-F) shows the stabilities of peptides SP-332, SP-333 and SP-304 when incubated in SIF for two hours. The results demonstrate that SP-333, which has D-Asn at the N-terminus and D-Leu at the C-terminus, remained virtually 100% biologically active after a two hour incubation in SIF (FIG. 7A), and remained virtually intact to digestion with SIF after two hours (FIGS. 7F-1 & 7F-2). Subsequent incubation studies with SP-333 performed in SIF for up to 24 hours indicate that there is very little degradation even after 24 hours in SIF (FIG. 7G). The data indicated that SP-333 is stable against digestion with SIF for up to 24 hours. Peptide SP-332 with D-Leu at the C-terminus showed a minor reduction in potency following the 120 min incubation with SIF (FIG. 7B). Interestingly, the HPLC analyses of SP-332 did not reveal any clear-cut degradation of the peptide (FIG. 7E-1 & 7E2), also suggesting that this peptide is also almost completely resistant to proteolysis by SIF during the 2-hr incubation. On the other hand, peptide SP-304 lost about 30% of its potency following digestion with SIF for just one hour (FIG. 7C). The HPLC analysis of SP-304 following SIF incubation confirmed its degradation (FIG. 7D-1 & 7D-2). These results suggest that SP-304 undergoes substantial proteolysis following incubation with SIF within one hour.

Example 4 Cyclic GMP Stimulation Assays

The ability of the GCC agonist peptide to bind to and activate the intestinal GC-C receptor was tested using T84 human colon carcinoma cell line. Human T84 colon carcinoma cells were obtained from the American Type Culture Collection. Cells were grown in a 1:1 mixture of Ham's F-12 medium and Dulbecco's modified Eagle's medium (DMEM) supplemented with 10% fetal bovine serum, 100 U penicillin/ml, and 100 μg/ml streptomycin. The cells were fed fresh medium every third day and split at a confluence of approximately 80%.

Biological activity of the GCC agonist peptides was assayed as previously reported (Shailubhai, et al., Cancer Research 60, 5151-5157 (2000)). Briefly, the confluent monolayers of T-84 cells in 24-well plates were washed twice with 250 μl of DMEM containing 50 mM HEPES (pH 7.4), pre-incubated at 37° C. for 10 min with 250 μl of DMEM containing 50 mM HEPES (pH 7.4) and 1 mM isobutylmethylxanthine (IBMX), followed by incubation with GCC agonist peptides (0.1 nM to 10.mu.M) for 30 min. The medium was aspirated, and the reaction was terminated by the addition of 3% perchloric acid. Following centrifugation, and neutralization with 0.1 N NaOH, the supernatant was used directly for measurements of cGMP using an ELISA kit (Caymen Chemical, Ann Arbor, Mich.).

FIG. 6 shows results from experiments evaluating the potency of peptides (via cGMP stimulation assay) having structures similar to the 14-mer peptide SP-339, also referred to as linaclotide. SP-339 is a truncated analog of the E. coli enterotoxin ST peptide. SP-354 was found to be virtually identical to SP-339 in biological activity. Notably, peptide SP-353, which has a Ser residue at the 6^(th) position, was found to be more potent than SP-339, and was the most potent of all the peptides tested. Peptide SP-355 which has a D-Tyr at the C-terminus showed considerably less potency than the other peptides tested.

Example 5 Peggylated Peptides

An additional strategy to render peptides more resistant towards digestion by digestive proteases is to peggylate them at the N- and C-terminus. The peptide SP-333 was peggylated with the aminoethyloxy-ethyloxy-acetic acid (Aeea) group at the C-terminus (SP-347) or at the N-terminus (SP-350) or at both termini (SP-343). Cyclic GMP synthesis in T84 cells was measured by the method as described above.

The peptides SP-347 and SP-350 showed potencies comparable to SP-333 in their abilities to stimulate cGMP synthesis in T84 cells. However, peptide SP-343 was considerably less potent as compared to the other peptides tested. The poor activity of SP-343 might be due to the considerable steric hindrance afforded by the large Aeea groups at both termini.

Example 6 Combination of Guanylate Cyclase Receptor Agonists with Phosphodiesterase Inhibitors

Regulation of intracellular concentrations of cyclic nucleotides (i.e., cAMP and cGMP) and thus, signaling via these second messengers, has been generally considered to be governed by their rates of production versus their rates of destruction within cells. Thus, levels of cGMP in tissues and organs can also be regulated by the levels of expression of cGMP-specific phosphodiesterases (cGMP-PDE), which are generally overexpressed in cancer and inflammatory diseases. Therefore, a combination consisting of an agonist of GC-C with an inhibitor of cGMP-PDE might produce synergistic effect on levels of cGMP in the target tissues and organs.

Sulindac Sulfone (SS) and Zaprinast (ZAP) are two of the known inhibitors of cGMP-PDE and have been shown to induce apoptosis in cancer cells via a cGMP-dependent mechanism. SS and ZAP in combination with SP-304 or SP-333 were evaluated to see if these PDE inhibitors had any synergistic effects on intracellular accumulation of cGMP (FIG. 9-12). As the data show, SS at a concentration of 100 μM did not enhance intracellular accumulation of cGMP. However, the combination of SS with SP-304 stimulated cGMP production several-fold more then stimulation by SP-304 alone. This synergistic effect on cGMP levels was more pronounced when SP-304 were used at a 0.1 μM concentration (FIG. 10). Similar observations were made when SP-304 or SP-333 were used in combination with ZAP (FIG. 10, FIG. 11 and FIG. 12). These results suggest that the intracellular levels of cGMP are stabilized because SS inhibits cGMP-PDE that might be responsible for depletion of intracellular cGMP. Thus, the approach to use a combination of GCC agonist with a cGMP-PDE inhibitor is attractive.

For the results shown in FIG. 9, cyclic GMP synthesis in T84 cells was assessed essentially as described in Shailubhai et al., Cancer Research 60, 5151-5157 (2000). Briefly, confluent monolayers of T-84 cells in 24-well plates were washed twice with 250 μl of DMEM containing 50 mM HEPES (pH 7.4) and pre-incubated at 37° C. for 10 minutes with 250 μl of DMEM containing 50 mM HEPES (pH 7.4) and 1 mM isobutyl methylxanthine (IBMX). Monolayers of T84 cells were then incubated with 250 μl of DMEM containing 50 mM HEPES (pH 7.4) containing SP-304 or PDE inhibitors either alone or in combinations, as indicated below in the following experimental sets: 1) Control; 2) SP-304 (0.1 μM); 3) Sulindac Sulfone (100 μM); 4) Zaprinast (100 μM); 5) SP-304 (0.1 μM)+Sulindac Sulfone (100 μM); and 6) SP-304 (0.1 μM)+Zaprinast (100 μM). After the 30 min incubation, the medium was aspirated and the reaction was terminated by the addition of 3% perchloric acid. Following centrifugation and the addition of NaOH (0.1 N) to neutralize the pH, intracellular cGMP levels were determined in lysates using a cGMP ELISA kit (Cat. No. 581021; Cayman Chemical, Ann Arbor, Mich.). Incubations were performed in duplicate, and each sample was run in duplicate using the ELISA test.

For the results shown in FIG. 10, the method used was same as the one used for FIG. 9 except that the monolayers of T84 cells were incubated with 500 μl of DMEM containing 50 mM HEPES (pH 7.4) containing SP-304 (0.1 or 1.0 μM) or increasing concentrations of PDE inhibitors (0 to 750 μM) either alone or in combination with SP-304. After the 30 min incubation, the medium was aspirated and the reaction was terminated by the addition of 3% perchloric acid. Following centrifugation and the addition of NaOH (0.1 N) to neutralize the pH, intracellular cGMP levels were determined in lysates using a cGMP ELISA kit (Cat. No. 581021; Cayman Chemical, Ann Arbor, Mich.). Samples were run in triplicate using the ELISA test.

For the results shown in FIG. 11, the method used was same as the one used for FIG. 10 except that the monolayers of T84 cells were incubated with 500 μl of DMEM containing 50 mM HEPES (pH 7.4) containing SP-3333 (0.1 or 1.0 μM) or increasing concentrations of ZAP (0 to 500 μM) either alone or in combination with SP-333. After the 30 min incubation, the medium was aspirated and the reaction was terminated by the addition of 3% perchloric acid. Following centrifugation and the addition of NaOH (0.1 N) to neutralize the pH, intracellular cGMP levels were determined in lysates using a cGMP ELISA kit (Cat. No. 581021; Cayman Chemical, Ann Arbor, Mich.). Samples were run in triplicate using the ELISA test.

For the results shown in FIG. 12, the method used was same as the one used for FIG. 10 except that the monolayers of T84 cells were incubated with 500 μl of DMEM containing 50 mM HEPES (pH 7.4) containing SP-333 (0.1 μM) or increasing concentrations of Sulindac Sulfone (0 to 500 μM) either alone or in combination with SP-333. After the 30 min incubation, the medium was aspirated and the reaction was terminated by the addition of 3% perchloric acid. Following centrifugation and the addition of NaOH (0.1 N) to neutralize the pH, intracellular cGMP levels were determined in lysates using a cGMP ELISA kit (Cat. No. 581021; Cayman Chemical, Ann Arbor, Mich.). Samples were run in triplicate using the ELISA test.

Example 7 A Repeated Oral Dose Toxicity Study of SP-304 in Cynomolgus Monkeys

The primary purpose of this experiment was to evaluate the toxicity and pharmacokinetics of a repeated oral dose of SP-304 in cynomolgus monkeys. Treatment with a daily dose of 250 mg of SP-304 for 14 consecutive days was well tolerated by all of the monkeys, however the treatment consistently produced liquid feces and watery diarrhea (FIG. 14). Monkeys returned to normal stool consistency within 24-48 hours following the last dose of SP-304.

Example 8 SP-304 Treatment Improves Stool Consistency and Clears TNBS-Induced Intestinal Blockage in a TNBS-Induced Murine Model of Colitis

SP-304 is a superior analog of uroguanylin and an agonist of GC-C. The anal administration of trinitrobenzene sulphonic acid (TNBS) is typically used to produce intestinal blockage, resulting in poor stool consistency. As shown in FIG. 13, oral administration of SP-304 considerably improved stool consistency in mice treated with TNBS. Treatment with SP-304 at a dose between 0.05 to 0.5 mg/kg body weight was sufficient to completely restore the consistency score to the level observed in mice treated with phosphate buffer instead of TNBS (minus TNBS control). Sulfasalazine, a FDA approved drug used as a positive control, also restored normal stool consistency.

Example 9 A Randomized, Double-Blind, Placebo-Controlled, Single-, Ascending-, Oral-Dose Safety, Tolerability, and Pharmacokinetic Study of SP-304 in Healthy Adult Human Male and Female Volunteers

The objectives of this study were to assess the safety and pharmacokinetics of a single oral dose of SP-304 in healthy subjects. This was a phase 1, single-site, randomized, double-blind, placebo-controlled, single-, ascending-, oral-dose, sequential dose escalation study of SP-304 in fasted, healthy male and female subjects. A total of 9 cohorts utilizing 8 subjects per cohort (6 SP-304; 2 placebo) were utilized, totaling 71 volunteers administered drug (one volunteer dropping out). Each cohort was administered a single, oral dose or matching placebo administered in 10-fold diluted phosphate buffered saline (PBS) (240 mL). Subjects were only administered one dose of study treatment and could not be enrolled in subsequent cohorts. The nine cohort doses included 0.1, 0.3, 0.9, 2.7, 5.4, 8.1, 16.2, 24.3 mg and 48.6 mg SP-304.

Doses of SP-304

-   -   0.1 mg (6 active, 2 placebo)     -   0.3 mg (6 active, 2 placebo)     -   0.9 mg (6 active, 2 placebo)     -   2.7 mg (6 active, 2 placebo)     -   5.4 mg (6 active, 2 placebo)     -   8.1 mg (6 active, 2 placebo)     -   16.2 mg (5 active, 2 placebo)     -   24.3 mg (6 active, 2 placebo)     -   48.6 mg (6 active, 2 placebo)

The decision to proceed to the next cohort was made by the study sponsor and principal investigator after reviewing the preliminary blinded, safety information from the cohort. All safety data collected through the 48 hours after dosing were reviewed to assess tolerability of the dose level. A minimum of 3 evaluable subjects were required for the determination of safety and tolerability at each dose level.

The stopping criteria were: 1) clinically significant adverse events [including clinically significant changes in laboratory or electrocardiogram (ECG) parameters] in ≧4 subjects (collectively within a cohort), or 2) 1 drug related, serious adverse event (SAE). No higher doses were to be administered if one of these criteria was met. Otherwise, the study could proceed to the next higher dose cohort.

Safety was monitored by physical examinations, vital signs, clinical laboratory tests (hematology, chemistry, urinalysis, fecal occult blood), ECG, and adverse experience assessments). Serial blood samples were collected 0, 0.5, 1, 1.5, 2, 3, 4, 6, 8, 16, 24, 36, and 48 hours after dosing. Plasma samples were assayed by a validated method for SP-304, and pharmacokinetic parameters calculated. Pharmacodynamic endpoints that were evaluated included time to first stool, stool frequency (48-hour period), and stool consistency (48-hour period) using the Bristol Stool Form Scale (BSFS).

The phase 1 study (Protocol No. SP-SP304101-08) used an oral solution prepared by a registered licensed pharmacist at the investigation site not more than one hour before administration of dose.

The primary objectives of this clinical evaluation were to determine safety, toxicity and systemic absorption of a single oral dose of SP-304. The data indicated that SP-304 was well-tolerated at all dosage levels and there were no severe adverse events (SAEs). The most prevalent adverse event (AE) observed during this study was grade I diarrhea (12.7%), as defined using the Common Terminology Criteria for Adverse Events (CTCAE), which is an increase in the number of bowel movements from 1 and <4 in a 24-hour period. Notably, SP-304 was expected to promote bowel movement, thus the increase in number of bowel movements was considered to be related to the pharmacodynamic (PD) action of SP-304.

The effect of a single oral dose of SP-304 on stool consistency, as judged by the Bristol form stool scale (BSFS), was also examined in volunteers. The BSFS score for the seven types of stool are:

Type 1: Separate hard lumps, like nuts (hard to pass)

Type 2: Sausage-shaped, but lumpy

Type 3: Like a sausage but with cracks on its surface

Type 4: Like a sausage or snake, smooth and soft

Type 5: Soft blobs with clear cut edges (passed easily)

Type 6: Fluffy pieces with ragged edges, a mushy stool

Type 7: Entirely liquid

Types 1 and 2 indicate constipation, with 3 and 4 being the “ideal stools” especially the latter, as they are the easiest to pass, and 5-7 score indicate further tending towards diarrhea or urgency.

FIG. 15A-B shows the effect of a single dose of SP-304 or placebo on BSFS score in volunteers treated with SP-304 ranging from 0.1 mg up to a maximum of 48.6 mg dose. The data indicate that treatment with SP-304 produced an increase in BSFS score in volunteers, relative to placebo-treated volunteers, reflecting a change in stool consistency towards a looser bowel movement in SP-304 treated volunteers. These results indicate that SP-304 has the potential to normalize bowel movement and to relieve the discomfort due to chronic constipation.

FIG. 16 shows the effect of a single dose of SP-304 or placebo on the time to first stool in the 24 hours period following dosing. The data indicate that SP-304 treatment significantly decreased the time to first bowel movement from 10.6 hours in volunteers treated with placebo to about 3 to 6 hours, following SP-304 treatment at doses ranging from 2.7 to 48.6 mg.

Example 10 SP-304 Ameliorates Inflammation in DSS-Induced Colitis in BDF-1 Mice

The cGMP pathway mediates the anti-inflammatory effects of cellular molecules such as nitric oxide and heme oxygenase-1. Therapies that induce cGMP (phosphodiesterase-4 inhibitors) have demonstrated efficacy in murine models of IBD. The anti-inflammatory effects of the GCC agonist SP-304 were evaluated in a murine model of ulcerative colitis, the DSS-induced colitis model.

Forty eight BDF1 mice were divided into 8 treatment groups (6 mice/group). One group was not exposed to DSS (untreated control) and groups 2-10 were treated with 5% DSS in the drinking water. DSS was refreshed daily. All mice were weighed on day −1, and treated with the test materials beginning on day −1. 4 hrs post dosing on Day 0, DSS was placed in the drinking water of groups 2-8 and DSS remained in the water until the end of the study. The test agents were administered at 9 AM daily until day 7. Animals were treated with a single dose of test agents and the groups were as follows:

1. No DSS exposure—PBS gavage (No DSS control)

2. 5% DSS+PBS (Vehicle control)

3. 5% DSS+80 mg/kg Sulfasalazine (positive control)

4. 5% DSS+0.005 mg/kg SP-304

5. 5% DSS+0.05 mg/kg SP-304

6. 5% DSS+0.5 mg/kg SP-304

7. 5% DSS+2.5 mg/kg SP-304

8. 5% DSS+50 mg/kg SP-304

All doses were administered by oral gavage using a 0.1 ml dose per 10 g body weight. To avoid cage-to-cage variation, different treatment groups were housed in the same cage and animals were ear punched for identification purposes. Mice were sacrificed on day 7, 4-6 hrs post last dosing. The animals were also subjected to internal examination of the major organs for any gross abnormalities. The distal section of the large intestine (sufficient for histopathological examination) was removed and fixed in Carnoy's solution and embedded in paraffin. Two non-serial sections per slide were cut and H&E stained for visual severity score analysis. All slides were scored in a blinded manner.

Histopathology Scoring

0 normal

1 all crypts remaining but look abnormal, all muscle intact

2 less than 90% crypts remaining, all muscle intact

3 less than 75% crypts remaining, majority muscle intact

4 less than 10% crypts remaining, most of muscle degraded

5 no crypts left, muscle degraded

Five different sections of the tissue were examined for histopathological scoring and the scores were averaged for each mouse. The histopathology scores in FIG. 17 are expressed as an average of 6 mice. As shown in FIG. 17, the data indicate that treatment of mice with DSS produced mild inflammation in the large intestine. As expected, the severity of the inflammation was considerably reduced in mice treated with sulfasalazine. Similarly, mice treated with SP-304 doses ranging from 0.005 to 5 mg/kg/body weight also showed reduced inflammation in the colon tissue. These results indicate that oral administration with SP-304 ameliorated DSS-induced inflammation in the colon tissue. The treatment with SP-304 did not change the colon weight considerably.

Example 11 SP-304 Ameliorates Inflammation in TNBS-Induced Colitis in BDF-1 Mice

Anal administration of TNBS is widely used to induce inflammation in the colon of mice and rats. The TNBS-induced ulcerative colitis is commonly used model for experimental colitis in mice for evaluation of drugs to be used for treatment of IBD in humans. To evaluate the anti-inflammatory effects of the GCC agonist SP-304, ninety BDF-1 mice were randomly divided into 9 groups of 10 each as follows:

1. No TNBS exposure—PBS gavage (No TNBS control)

2. TNBS+PBS (Vehicle control)

3. TNBS+80 mg/kg Sulfasalazine (positive control)

4. TNBS+0.0005 mg/kg SP-304

5. TNBS+0.005 mg/kg SP-304

6. TNBS+0.05 mg/kg SP-304

7. TNBS+0.5 mg/kg SP-304

8. TNBS+2.5 mg/kg SP-304

9. TNBS+50 mg/kg SP-304

Groups 2-9 were given 2.5 mg of TNBS in 50% ethanol through anal route using a rubber catheter on day 0. Mice were given a single dose of SP-304 at 9 am everyday for seven days. At the end of the study mice were sacrificed by cervical dislocation. The distal large intestine was removed and fixed in Carnoy's fixative. Samples were paraffin embedded and 2 non-serial sections per sample were cut & mounted on one slide before staining with H&E. Slides of intestinal tissues was scored. Blinded histological sections were observed microscopically and assigned a severity score of 0 to 5, as per the scoring system described in FIG. 8. For every mouse 5 cross sectional areas of the large intestine were assessed. Results are expressed as an average. As shown in FIG. 18, treatment with SP-304 at a dose as low as 0.05 mg/kg body weight significantly reduced colonic inflammation. Interestingly, the potency of SP-304 even at concentrations as low as 0.05 mg·kg was comparable to sulfasalazine given at a dose of 80 mg/kg body weight.

Example 12 Repeated Daily Dose of SP-304 Produced Severe Diarrhea in Cynomolgus Monkeys

Male (n=4) and female (n=4) monkeys were given a daily dose (1 or 10 or 75 mg/kg body weight) of SP-304 repeatedly for 28 days. Effect of treatment on stool consistency was recorded three times a day. As shown in FIG. 19, oral treatment with SP-304 produced diarrhea/watery stools in both sexes. However, female monkeys showed a more pronounced effect. In females, a dose of 10 mg/kg body weight produced severe diarrhea consistently. Therefore, SP-304 was used at 10 mg/kg body weight in the subsequent experiments. Similar results were obtained with SP-333.

Example 13 Repeated Dose of SP-304 Produced Severe Bloating in the Proximal Intestines in Mice

The objective of this experiment was to determine the primary site of action for orally administered SP-304 with respect to its ability to stimulate water secretion in the gastrointestinal tract. Under normal physiological circumstances, water secretion occurs primarily in the duodenum and the secreted water is then reabsorbed in the ileum. Mice (females, n=6; males, n=6) were given a single dose of SP-304 by oral gavage and sacrificed 30 minutes later. The gastrointestinal tract was examined for signs of bloating which indicates excessive secretion of water. As shown in Table VIII, SP-304 produced bloating only in the stomach and in the proximal intestine (duodenum and jejunum) but not in cecum or distal intestine (ileum and colon). These results demonstrate that orally administered SP-304 caused water secretion in the duodenum/jejunum. Thus, the site of action of SP-304 is primarily in the duodenum and jejunum portions of the gastrointestinal tract.

TABLE VIII SP-304 oral administration produced severe bloating in proximal intestine of mice. Mice (6 males and 6 females) were orally administered with SP-304 (1200 mg/kg body weight). After 30 minutes, mice were sacrificed and immediately opened to determine if SP-304 administration had caused bloating, due to excessive secretion of fluid, in different segments of the GI tract. Results are expressed as % number of mice showing bloating in various parts of the GI tract. Male Mice Female Mice Number of Animals Number of Animals GI Tract with Bloating (% of total) with Bloating (% of total) Segment n = 6 n = 6 Stomach 3 (50%) 2 (33%) Duodenum 2 (33%) 2 (33%) Jejunum  6 (100%)  6 (100%) Cecum 1 (2%)  0 (0%) 

Example 14 Formulations of SP-304 for Different GI Diseases

As indicated by the data in Table VIII, orally administered SP-304 acts in the proximal portions of the GI tract (duodenum, jejunum) to stimulate water secretion. Thus, a formulation for delivery of SP-304 to this region should demonstrate improved efficacy for the treatment of chronic constipation, IBS-C and other diseases of the proximal intestine. This is because such a formulation would more effectively stimulate the secretion of water and promote the normalization of bowel movement in patients suffering from these conditions. In addition, aggregation of SP-304, which occurs beginning at 1.0 mg/ml and is promoted by acidic conditions, would be minimized in a pH dependent release formulation designed to release at higher pH. Thus, a pH dependent release formulation of SP-304 comprising the Eudragit polymer was tested for efficacy of release at pH greater than 5.5, which would target release to the duodenum. As shown in FIG. 20, gelatin capsules coated with Eudragit polymer for dissolution at pH greater than 5.5 did not disintegrate and SP-304 was not released under acidic conditions at pH 1 or 2.5. As expected, incubation of the capsule at pH 5.7 released SP-304 within 20 minutes and within 60 minutes most of the peptide was released. The released SP-304 was biologically active as determined in the T84 cells bioassay (see FIG. 21).

For the treatment of IBD and other diseases or disorders of the distal GI tract, it is advantageous to develop a formulation which targets GCC agonists to the distal GI tract, particularly the terminal ileum. This is particularly the case for the treatment of IBD which is often complicated by diarrhea. Thus, oral administration of a GCC agonist would likely be counterproductive for IBD due to the stimulation of water secretion in the duodenum. This problem would be circumvented by a formulation that targeted delivery to the terminal ileum. A pH dependent release formulation of SP-304 was therefore tested for efficacy of release at pH greater than 7, which would target release to the terminal ileum. As shown in FIGS. 20 and 21, the Eudragit polymer formulation released the SP-304 at pH 7.2 and the released SP-304 was biologically active.

Example 15 SP-304 and SP-333 Formulated in Eudragit Polymer Coating for Delivery at or Above pH 7 Minimized Diarrhea in Cynomolgus Monkeys

As shown in FIG. 22, SP-304 formulated in gelatin capsules coated with Eudragit polymer (for dissolution at pH above 7) produced considerably less incidences of diarrhea as compared to the uncoated capsules containing the same dose of SP-304 (10 mg/kg body weight). These results demonstrate that the delivery of a GCC agonist to the distal intestine reduces the incidence of diarrhea which would otherwise be expected from oral administration of the agonist. Thus, such a formulation would be preferred for the treatment of IBD, colon cancer and other diseases of the distal intestine.

SP-333 is a GCC agonist which was designed for increased stability against the proteolysis which would normally occur in the intestinal fluid. Thus, this peptide would also be useful for the treatment of IBD, colon cancer and other diseases of the distal intestine. SP-333 was formulated in gelatin capsules coated with Eudragit polymer for dissolution at pH above 7. As shown in FIG. 23, the coated capsules produced a considerably lower incidence of diarrhea compared to the uncoated capsules. 

1. A GCC agonist formulation comprising (1) a core, which contains at least one GCC agonist peptide, and (2) one or more targeting materials selected from the group consisting of a pH-dependent polymer, a swellable polymer, and a degradable composition, wherein the GCC agonist peptide is selected from the group consisting of SEQ ID NOs: 1-249.
 2. (canceled)
 3. (canceled)
 4. The GCC agonist formulation of claim 1, wherein the formulation is for an oral route of administration.
 5. The GCC agonist formulation of claim 1, wherein the formulation is optimized for delivery of a GCC agonist to the duodenum, jejunum, ileum, terminal ileum, or ascending colon.
 6. The GCC agonist formulation of claim 5, wherein the formulation comprises one or more pH dependent polymers which degrade in a pH range of 4.5 to 5.5, in a pH range of 5.5 to 6.5, or in a pH range of 6.5 to 7.5.
 7. (canceled)
 8. (canceled)
 9. The GCC agonist formulation of claim 1, wherein the pH dependent polymer is selected from the group consisting of a methacrylic acid copolymer, a polyvinyl acetate phthalate, a hydroxypropylmethylcellulose phthalate, a cellulose acetate trimelliate, a cellulose acetate phthalate, or a hydroxypropyl methyl cellulose acetate succinate.
 10. (canceled)
 11. The GCC agonist formulation of claim 8, wherein the methacrylic acid copolymer is selected from among the EUDRAGIT polymers.
 12. (canceled)
 13. The GCC agonist formulation of claim 5, wherein the formulation comprises one or more pH dependent polymers and a swellable polymer.
 14. The GCC agonist formulation of claim 13, wherein the formulation comprises two pH dependent polymers which degrade in a pH range of 6.5 to 7.5 and wherein the swellable polymerforms a layer between the two pH dependent polymers.
 15. The GCC agonist formulation of claim 13, wherein the swellable polymer is selected from the group consisting of an acrylic copolymer, polyvinylacetate, and cellulose derivatives.
 16. (canceled)
 17. The GCC agonist formulation of claim 13, further comprising a pore forming agent.
 18. (canceled)
 19. The GCC agonist formulation of claim 1, wherein the formulation comprises a degradable composition.
 20. (canceled)
 21. The GCC agonist formulation of claim 19, further comprising a material selected from the group consisting of cellulose acetate phthalate, hydroxy propyl methyl cellulose acetate succinate, EUDRAGIT L100 and EUDRAGIT L30D-55, wherein the material forms an outer coating over the degradable composition.
 22. The GCC agonist formulation of claim 19, wherein the degradable composition is a carrier molecule linked to the GCC agonist by a covalent bond, wherein the covalent bond is stable in the stomach and small intestines but labile in the lower gastrointestinal tract, especially the colon.
 23. (canceled)
 24. (canceled)
 25. A method for treating or preventing a gastrointestinal disease or disorder in a subject in need thereof, comprising administering to the subject a GCC agonist formulation comprising (1) a core, which contains at least one GCC agonist peptide, and (2) one or more targeting materials selected from the group consisting of a pH-dependent polymer, a swellable polymer, and a degradable composition, wherein the GCC agonist peptide is selected from the group consisting of SEQ ID NOs: 1-249.
 26. The method of claim 25, wherein the formulation comprises one or more pH dependent polymers which degrade in a pH range of 4.5 to 5.5, in a pH range of 5.5 to 6.5, or in a pH range of 6.5 to 7.5.
 27. The method of claim 26, wherein the gastrointestinal disease or disorder is selected from the group consisting of irritable bowel syndrome, non-ulcer dyspepsia, chronic intestinal pseudo-obstruction, functional dyspepsia, colonic pseudo-obstruction, duodenogastric reflux, gastro esophageal reflux disease, chronic idiopathic constipation, gastroparesis, heartburn, gastric cancer, H. pylori infection, ileitis (post-operative ileitis), Crohn's disease, ulcerative colitis, terminal ileitis, and colon cancer.
 28. (canceled)
 29. (canceled)
 30. (canceled)
 31. (canceled)
 32. (canceled)
 33. (canceled)
 34. The method of claim 25, further comprising administering to the subject an effective amount of an inhibitor of a cGMP-specific phosphodiesterase.
 35. (canceled)
 36. The method of claim 26, further comprising administering to the subject an effective amount of at least one laxative.
 37. (canceled)
 38. The method of claim 25, further comprising administering to the subject an effective amount of at least one anti-inflammatory agent.
 39. The method of claim 25, wherein the subject is a human. 